contains 147 rules |
System Settings
[ref]groupContains rules that check correct system settings. |
contains 105 rules |
Installing and Maintaining Software
[ref]groupThe following sections contain information on
security-relevant choices during the initial operating system
installation process and the setup of software
updates. |
contains 18 rules |
System and Software Integrity
[ref]groupSystem and software integrity can be gained by installing antivirus, increasing
system encryption strength with FIPS, verifying installed software, enabling SELinux,
installing an Intrusion Prevention System, etc. However, installing or enabling integrity
checking tools cannot prevent intrusions, but they can detect that an intrusion
may have occurred. Requirements for integrity checking may be highly dependent on
the environment in which the system will be used. Snapshot-based approaches such
as AIDE may induce considerable overhead in the presence of frequent software updates. |
contains 7 rules |
Software Integrity Checking
[ref]groupBoth the AIDE (Advanced Intrusion Detection Environment)
software and the RPM package management system provide
mechanisms for verifying the integrity of installed software.
AIDE uses snapshots of file metadata (such as hashes) and compares these
to current system files in order to detect changes.
The RPM package management system can conduct integrity
checks by comparing information in its metadata database with
files installed on the system. |
contains 4 rules |
Verify Integrity with RPM
[ref]groupThe RPM package management system includes the ability
to verify the integrity of installed packages by comparing the
installed files with information about the files taken from the
package metadata stored in the RPM database. Although an attacker
could corrupt the RPM database (analogous to attacking the AIDE
database as described above), this check can still reveal
modification of important files. To list which files on the system differ from what is expected by the RPM database:
$ rpm -qVa
See the man page for rpm to see a complete explanation of each column. |
contains 3 rules |
Verify File Hashes with RPM
[ref]ruleWithout cryptographic integrity protections, system
executables and files can be altered by unauthorized users without
detection.
The RPM package management system can check the hashes of
installed software packages, including many that are important to system
security.
To verify that the cryptographic hash of system files and commands matches vendor
values, run the following command to list which files on the system
have hashes that differ from what is expected by the RPM database:
$ rpm -Va --noconfig | grep '^..5'
A "c" in the second column indicates that a file is a configuration file, which
may appropriately be expected to change. If the file was not expected to
change, investigate the cause of the change using audit logs or other means.
The package can then be reinstalled to restore the file.
Run the following command to determine which package owns the file:
$ rpm -qf FILENAME
The package can be reinstalled from a dnf repository using the command:
$ sudo dnf reinstall PACKAGENAME
Alternatively, the package can be reinstalled from trusted media using the command:
$ sudo rpm -Uvh PACKAGENAME Rationale:The hashes of important files like system executables should match the
information given by the RPM database. Executables with erroneous hashes could
be a sign of nefarious activity on the system. Identifiers:
CCE-90841-8 References:
11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.3.8, 3.4.1, CCI-000366, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), PR.DS-6, PR.DS-8, PR.IP-1, Req-11.5, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
# Find which files have incorrect hash (not in /etc, because of the system related config files) and then get files names
files_with_incorrect_hash="$(rpm -Va --noconfig | grep -E '^..5' | awk '{print $NF}' )"
# From files names get package names and change newline to space, because rpm writes each package to new line
packages_to_reinstall="$(rpm -qf $files_with_incorrect_hash | tr '\n' ' ')"
dnf reinstall -y $packages_to_reinstall
|
Verify and Correct Ownership with RPM
[ref]ruleThe RPM package management system can check file ownership
permissions of installed software packages, including many that are
important to system security. After locating a file with incorrect
permissions, which can be found with
rpm -Va | awk '{ if (substr($0,6,1)=="U" || substr($0,7,1)=="G") print $NF }'
run the following command to determine which package owns it:
$ rpm -qf FILENAME
Next, run the following command to reset its permissions to
the correct values:
$ sudo rpm --setugids PACKAGENAME Warning:
Profiles may require that specific files be owned by root while the default owner defined
by the vendor is different.
Such files will be reported as a finding and need to be evaluated according to your policy
and deployment environment. Rationale:Ownership of binaries and configuration files that is incorrect
could allow an unauthorized user to gain privileges that they should
not have. The ownership set by the vendor should be maintained. Any
deviations from this baseline should be investigated. Identifiers:
CCE-90842-6 References:
1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9, 5.10.4.1, APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.07, DSS06.02, MEA02.01, 3.3.8, 3.4.1, CCI-001494, CCI-001496, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R4.2, CIP-003-8 R6, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, Req-11.5, SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000278-GPOS-00108 Remediation Shell script: (show)
Complexity: | high |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
# Declare array to hold set of RPM packages we need to correct permissions for
declare -A SETPERMS_RPM_DICT
# Create a list of files on the system having permissions different from what
# is expected by the RPM database
readarray -t FILES_WITH_INCORRECT_PERMS < <(rpm -Va --nofiledigest | awk '{ if (substr($0,6,1)=="U" || substr($0,7,1)=="G") print $NF }')
for FILE_PATH in "${FILES_WITH_INCORRECT_PERMS[@]}"
do
RPM_PACKAGE=$(rpm -qf "$FILE_PATH")
# Use an associative array to store packages as it's keys, not having to care about duplicates.
SETPERMS_RPM_DICT["$RPM_PACKAGE"]=1
done
# For each of the RPM packages left in the list -- reset its permissions to the
# correct values
for RPM_PACKAGE in "${!SETPERMS_RPM_DICT[@]}"
do
rpm --setugids "${RPM_PACKAGE}"
done
Remediation Ansible snippet: (show)
Complexity: | high |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list of files with incorrect ownership
command: rpm -Va --nodeps --nosignature --nofiledigest --nosize --nomtime --nordev
--nocaps --nolinkto --nomode
args:
warn: false
register: files_with_incorrect_ownership
failed_when: files_with_incorrect_ownership.rc > 1
changed_when: false
check_mode: false
tags:
- CCE-90842-6
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_ownership
- name: Create list of packages
command: rpm -qf "{{ item }}"
args:
warn: false
with_items: '{{ files_with_incorrect_ownership.stdout_lines | map(''regex_findall'',
''^[.]+[U|G]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
| list | unique }}'
register: list_of_packages
changed_when: false
check_mode: false
when: (files_with_incorrect_ownership.stdout_lines | length > 0)
tags:
- CCE-90842-6
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_ownership
- name: Correct file ownership with RPM
command: rpm --quiet --setugids '{{ item }}'
args:
warn: false
with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
| unique }}'
when: (files_with_incorrect_ownership.stdout_lines | length > 0)
tags:
- CCE-90842-6
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_ownership
|
Verify and Correct File Permissions with RPM
[ref]ruleThe RPM package management system can check file access permissions
of installed software packages, including many that are important
to system security.
Verify that the file permissions of system files
and commands match vendor values. Check the file permissions
with the following command:
$ sudo rpm -Va | awk '{ if (substr($0,2,1)=="M") print $NF }'
Output indicates files that do not match vendor defaults.
After locating a file with incorrect permissions,
run the following command to determine which package owns it:
$ rpm -qf FILENAME
Next, run the following command to reset its permissions to
the correct values:
$ sudo rpm --setperms PACKAGENAME Warning:
Profiles may require that specific files have stricter file permissions than defined by the
vendor.
Such files will be reported as a finding and need to be evaluated according to your policy
and deployment environment. Rationale:Permissions on system binaries and configuration files that are too generous
could allow an unauthorized user to gain privileges that they should not have.
The permissions set by the vendor should be maintained. Any deviations from
this baseline should be investigated. Identifiers:
CCE-90840-0 References:
1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9, 5.10.4.1, APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.07, DSS06.02, MEA02.01, 3.3.8, 3.4.1, CCI-001493, CCI-001494, CCI-001495, CCI-001496, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R4.2, CIP-003-8 R6, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), CM-6(a), PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, Req-11.5, SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099, SRG-OS-000278-GPOS-00108 Remediation Shell script: (show)
Complexity: | high |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
# Declare array to hold set of RPM packages we need to correct permissions for
declare -A SETPERMS_RPM_DICT
# Create a list of files on the system having permissions different from what
# is expected by the RPM database
readarray -t FILES_WITH_INCORRECT_PERMS < <(rpm -Va --nofiledigest | awk '{ if (substr($0,2,1)=="M") print $NF }')
for FILE_PATH in "${FILES_WITH_INCORRECT_PERMS[@]}"
do
# NOTE: some files maybe controlled by more then one package
readarray -t RPM_PACKAGES < <(rpm -qf "${FILE_PATH}")
for RPM_PACKAGE in "${RPM_PACKAGES[@]}"
do
# Use an associative array to store packages as it's keys, not having to care about duplicates.
SETPERMS_RPM_DICT["$RPM_PACKAGE"]=1
done
done
# For each of the RPM packages left in the list -- reset its permissions to the
# correct values
for RPM_PACKAGE in "${!SETPERMS_RPM_DICT[@]}"
do
rpm --restore "${RPM_PACKAGE}"
done
Remediation Ansible snippet: (show)
Complexity: | high |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list of files with incorrect permissions
command: rpm -Va --nodeps --nosignature --nofiledigest --nosize --nomtime --nordev
--nocaps --nolinkto --nouser --nogroup
args:
warn: false
register: files_with_incorrect_permissions
failed_when: files_with_incorrect_permissions.rc > 1
changed_when: false
check_mode: false
tags:
- CCE-90840-0
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_permissions
- name: Create list of packages
command: rpm -qf "{{ item }}"
args:
warn: false
with_items: '{{ files_with_incorrect_permissions.stdout_lines | map(''regex_findall'',
''^[.]+[M]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
| list | unique }}'
register: list_of_packages
changed_when: false
check_mode: false
when: (files_with_incorrect_permissions.stdout_lines | length > 0)
tags:
- CCE-90840-0
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_permissions
- name: Correct file permissions with RPM
command: rpm --setperms '{{ item }}'
args:
warn: false
with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
| unique }}'
when: (files_with_incorrect_permissions.stdout_lines | length > 0)
tags:
- CCE-90840-0
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_permissions
|
Verify Integrity with AIDE
[ref]groupAIDE conducts integrity checks by comparing information about
files with previously-gathered information. Ideally, the AIDE database is
created immediately after initial system configuration, and then again after any
software update. AIDE is highly configurable, with further configuration
information located in /usr/share/doc/aide-VERSION . |
contains 1 rule |
Install AIDE
[ref]ruleThe aide package can be installed with the following command:
$ sudo dnf install aide Rationale:The AIDE package must be installed if it is to be available for integrity checking. Identifiers:
CCE-90843-4 References:
BP28(R51), 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-002696, CCI-002699, CCI-001744, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, 1034, 1288, 1341, 1417, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, CM-6(a), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, SRG-OS-000363-GPOS-00150, SRG-OS-000445-GPOS-00199 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "aide" ; then
dnf install -y "aide"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure aide is installed
package:
name: aide
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90843-4
- CJIS-5.10.1.3
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_aide_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_aide
class install_aide {
package { 'aide':
ensure => 'installed',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
package --add=aide
Remediation script: (show)
[[packages]]
name = "aide"
version = "*"
|
Federal Information Processing Standard (FIPS)
[ref]groupThe Federal Information Processing Standard (FIPS) is a computer security standard which
is developed by the U.S. Government and industry working groups to validate the quality
of cryptographic modules. The FIPS standard provides four security levels to ensure
adequate coverage of different industries, implementation of cryptographic modules, and
organizational sizes and requirements.
FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules
utilize authentication that meets industry and government requirements. For government systems, this allows
Security Levels 1, 2, 3, or 4 for use on Red Hat Enterprise Linux 9.
See http://csrc.nist.gov/publications/PubsFIPS.html for more information. |
contains 1 rule |
Enable FIPS Mode
[ref]ruleTo enable FIPS mode, run the following command:
fips-mode-setup --enable
The fips-mode-setup command will configure the system in
FIPS mode by automatically configuring the following:
- Setting the kernel FIPS mode flag (
/proc/sys/crypto/fips_enabled ) to 1 - Creating
/etc/system-fips - Setting the system crypto policy in
/etc/crypto-policies/config to FIPS - Loading the Dracut
fips module
Warning:
The system needs to be rebooted for these changes to take effect. Rationale:Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to
protect data. The operating system must implement cryptographic modules adhering to the higher
standards approved by the federal government since this provides assurance they have been tested
and validated. Identifiers:
CCE-88742-2 References:
CCI-000068, CCI-000803, CCI-002450, 1446, CIP-003-8 R4.2, CIP-007-3 R5.1, SC-12(2), SC-12(3), IA-7, SC-13, CM-6(a), SC-12, FCS_COP.1(1), FCS_COP.1(2), FCS_COP.1(3), FCS_COP.1(4), FCS_CKM.1, FCS_CKM.2, FCS_TLSC_EXT.1, FCS_RBG_EXT.1, SRG-OS-000478-GPOS-00223, SRG-OS-000396-GPOS-00176, SRG-OS-000120-VMM-000600, SRG-OS-000478-VMM-001980, SRG-OS-000396-VMM-001590 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_system_crypto_policy='FIPS'
fips-mode-setup --enable
stderr_of_call=$(update-crypto-policies --set ${var_system_crypto_policy} 2>&1 > /dev/null)
rc=$?
if test "$rc" = 127; then
echo "$stderr_of_call" >&2
echo "Make sure that the script is installed on the remediated system." >&2
echo "See output of the 'dnf provides update-crypto-policies' command" >&2
echo "to see what package to (re)install" >&2
false # end with an error code
elif test "$rc" != 0; then
echo "Error invoking the update-crypto-policies script: $stderr_of_call" >&2
false # end with an error code
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
System Cryptographic Policies
[ref]groupLinux has the capability to centrally configure cryptographic polices. The command
update-crypto-policies is used to set the policy applicable for the various
cryptographic back-ends, such as SSL/TLS libraries. The configured cryptographic
policies will be the default policy used by these backends unless the application
user configures them otherwise. When the system has been configured to use the
centralized cryptographic policies, the administrator is assured that any application
that utilizes the supported backends will follow a policy that adheres to the
configured profile.
Currently the supported backends are:
- GnuTLS library
- OpenSSL library
- NSS library
- OpenJDK
- Libkrb5
- BIND
- OpenSSH
Applications and languages which rely on any of these backends will follow the
system policies as well. Examples are apache httpd, nginx, php, and others. |
contains 2 rules |
Configure System Cryptography Policy
[ref]ruleTo configure the system cryptography policy to use ciphers only from the FIPS
policy, run the following command:
$ sudo update-crypto-policies --set FIPS
The rule checks if settings for selected crypto policy are configured as expected. Configuration files in the /etc/crypto-policies/back-ends are either symlinks to correct files provided by Crypto-policies package or they are regular files in case crypto policy customizations are applied.
Crypto policies may be customized by crypto policy modules, in which case it is delimited from the base policy using a colon.Warning:
The system needs to be rebooted for these changes to take effect. Warning:
System Crypto Modules must be provided by a vendor that undergoes
FIPS-140 certifications.
FIPS-140 is applicable to all Federal agencies that use
cryptographic-based security systems to protect sensitive information
in computer and telecommunication systems (including voice systems) as
defined in Section 5131 of the Information Technology Management Reform
Act of 1996, Public Law 104-106. This standard shall be used in
designing and implementing cryptographic modules that Federal
departments and agencies operate or are operated for them under
contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf
To meet this, the system has to have cryptographic software provided by
a vendor that has undergone this certification. This means providing
documentation, test results, design information, and independent third
party review by an accredited lab. While open source software is
capable of meeting this, it does not meet FIPS-140 unless the vendor
submits to this process. Rationale:Centralized cryptographic policies simplify applying secure ciphers across an operating system and
the applications that run on that operating system. Use of weak or untested encryption algorithms
undermines the purposes of utilizing encryption to protect data. Identifiers:
CCE-83450-7 References:
164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.312(e)(1), 164.312(e)(2)(ii), 1446, CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1, AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13, SC-12(2), SC-12(3), FCS_COP.1(1), FCS_COP.1(2), FCS_COP.1(3), FCS_COP.1(4), FCS_CKM.1, FCS_CKM.2, FCS_TLSC_EXT.1, SRG-OS-000396-GPOS-00176, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174 Remediation Shell script: (show)
var_system_crypto_policy='FIPS'
stderr_of_call=$(update-crypto-policies --set ${var_system_crypto_policy} 2>&1 > /dev/null)
rc=$?
if test "$rc" = 127; then
echo "$stderr_of_call" >&2
echo "Make sure that the script is installed on the remediated system." >&2
echo "See output of the 'dnf provides update-crypto-policies' command" >&2
echo "to see what package to (re)install" >&2
false # end with an error code
elif test "$rc" != 0; then
echo "Error invoking the update-crypto-policies script: $stderr_of_call" >&2
false # end with an error code
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_system_crypto_policy # promote to variable
set_fact:
var_system_crypto_policy: !!str FIPS
tags:
- always
- name: Configure System Cryptography Policy
lineinfile:
path: /etc/crypto-policies/config
regexp: ^(?!#)(\S+)$
line: '{{ var_system_crypto_policy }}'
create: true
tags:
- CCE-83450-7
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-12(2)
- NIST-800-53-SC-12(3)
- NIST-800-53-SC-13
- configure_crypto_policy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- name: Verify that Crypto Policy is Set (runtime)
command: /usr/bin/update-crypto-policies --set {{ var_system_crypto_policy }}
tags:
- CCE-83450-7
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-12(2)
- NIST-800-53-SC-12(3)
- NIST-800-53-SC-13
- configure_crypto_policy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
|
Configure SSH to use System Crypto Policy
[ref]ruleCrypto Policies provide a centralized control over crypto algorithms usage of many packages.
SSH is supported by crypto policy, but the SSH configuration may be
set up to ignore it.
To check that Crypto Policies settings are configured correctly, ensure that
the CRYPTO_POLICY variable is either commented or not set at all
in the /etc/sysconfig/sshd . Rationale:Overriding the system crypto policy makes the behavior of the SSH service violate expectations,
and makes system configuration more fragmented. Identifiers:
CCE-83445-7 References:
164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.312(e)(1), 164.312(e)(2)(ii), CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1, AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13, SRG-OS-000250-GPOS-00093 Remediation Shell script: (show)
SSH_CONF="/etc/sysconfig/sshd"
sed -i "/^\s*CRYPTO_POLICY.*$/d" $SSH_CONF
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Configure SSH to use System Crypto Policy
lineinfile:
dest: /etc/sysconfig/sshd
state: absent
regexp: ^\s*CRYPTO_POLICY.*$
tags:
- CCE-83445-7
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-13
- configure_ssh_crypto_policy
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
|
Sudo , which stands for "su 'do'", provides the ability to delegate authority
to certain users, groups of users, or system administrators. When configured for system
users and/or groups, Sudo can allow a user or group to execute privileged commands
that normally only root is allowed to execute.
For more information on Sudo and addition Sudo configuration options, see
https://www.sudo.ws.
|
contains 4 rules |
Install sudo Package
[ref]ruleThe sudo package can be installed with the following command:
$ sudo dnf install sudo Rationale:sudo is a program designed to allow a system administrator to give
limited root privileges to users and log root activity. The basic philosophy
is to give as few privileges as possible but still allow system users to
get their work done. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "sudo" ; then
dnf install -y "sudo"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure sudo is installed
package:
name: sudo
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83523-1
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_sudo_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_sudo
class install_sudo {
package { 'sudo':
ensure => 'installed',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
package --add=sudo
Remediation script: (show)
[[packages]]
name = "sudo"
version = "*"
|
Ensure Users Re-Authenticate for Privilege Escalation - sudo !authenticate
[ref]ruleThe sudo !authenticate option, when specified, allows a user to execute commands using
sudo without having to authenticate. This should be disabled by making sure that the
!authenticate option does not exist in /etc/sudoers configuration file or
any sudo configuration snippets in /etc/sudoers.d/ . Rationale:Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate. Identifiers:
CCE-83544-7 References:
BP28(R5), BP28(R59), 1, 12, 15, 16, 5, DSS05.04, DSS05.10, DSS06.03, DSS06.10, CCI-002038, 4.3.3.5.1, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-11, CM-6(a), PR.AC-1, PR.AC-7, SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158, SRG-OS-000373-VMM-001470, SRG-OS-000373-VMM-001480, SRG-OS-000373-VMM-001490 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
for f in /etc/sudoers /etc/sudoers.d/* ; do
if [ ! -e "$f" ] ; then
continue
fi
matching_list=$(grep -P '^(?!#).*[\s]+\!authenticate.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "!authenticate" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
/usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
fi
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Find /etc/sudoers.d/ files
find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- CCE-83544-7
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_remove_no_authenticate
- name: Remove lines containing !authenticate from sudoers files
replace:
regexp: (^(?!#).*[\s]+\!authenticate.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- CCE-83544-7
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_remove_no_authenticate
|
Ensure Users Re-Authenticate for Privilege Escalation - sudo NOPASSWD
[ref]ruleThe sudo NOPASSWD tag, when specified, allows a user to execute
commands using sudo without having to authenticate. This should be disabled
by making sure that the NOPASSWD tag does not exist in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . Rationale:Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate. Identifiers:
CCE-83536-3 References:
BP28(R5), BP28(R59), 1, 12, 15, 16, 5, DSS05.04, DSS05.10, DSS06.03, DSS06.10, CCI-002038, 4.3.3.5.1, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-11, CM-6(a), PR.AC-1, PR.AC-7, SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158, SRG-OS-000373-VMM-001470, SRG-OS-000373-VMM-001480, SRG-OS-000373-VMM-001490 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
for f in /etc/sudoers /etc/sudoers.d/* ; do
if [ ! -e "$f" ] ; then
continue
fi
matching_list=$(grep -P '^(?!#).*[\s]+NOPASSWD[\s]*\:.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "NOPASSWD" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
/usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
fi
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Find /etc/sudoers.d/ files
find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- CCE-83536-3
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_remove_nopasswd
- name: Remove lines containing NOPASSWD from sudoers files
replace:
regexp: (^(?!#).*[\s]+NOPASSWD[\s]*\:.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- CCE-83536-3
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_remove_nopasswd
|
Ensure Users Re-Authenticate for Privilege Escalation - sudo
[ref]ruleThe sudo NOPASSWD and !authenticate option, when
specified, allows a user to execute commands using sudo without having to
authenticate. This should be disabled by making sure that
NOPASSWD and/or !authenticate do not exist in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ ." Rationale:Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate. Identifiers:
CCE-83543-9 References:
1, 12, 15, 16, 5, DSS05.04, DSS05.10, DSS06.03, DSS06.10, CCI-002038, 4.3.3.5.1, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-11, CM-6(a), PR.AC-1, PR.AC-7, SRG-OS-000373-GPOS-00156 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
for f in /etc/sudoers /etc/sudoers.d/* ; do
if [ ! -e "$f" ] ; then
continue
fi
matching_list=$(grep -P '^(?!#).*[\s]+NOPASSWD[\s]*\:.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "NOPASSWD" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
/usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
fi
done
for f in /etc/sudoers /etc/sudoers.d/* ; do
if [ ! -e "$f" ] ; then
continue
fi
matching_list=$(grep -P '^(?!#).*[\s]+\!authenticate.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "!authenticate" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
/usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
fi
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Find /etc/sudoers.d/ files
find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- CCE-83543-9
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
- name: Remove lines containing NOPASSWD from sudoers files
replace:
regexp: (^(?!#).*[\s]+NOPASSWD[\s]*\:.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- CCE-83543-9
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
- name: Find /etc/sudoers.d/ files
find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- CCE-83543-9
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
- name: Remove lines containing !authenticate from sudoers files
replace:
regexp: (^(?!#).*[\s]+\!authenticate.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- CCE-83543-9
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
|
System Tooling / Utilities
[ref]groupThe following checks evaluate the system for recommended base packages -- both for installation
and removal. |
contains 1 rule |
Install rear Package
[ref]ruleThe rear package can be installed with the following command:
$ sudo dnf install rear Rationale:rear contains the Relax-and-Recover (ReaR) utility. ReaR produces a bootable
image of a system and restores from backup using this image. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if ! grep -q aarch64 /proc/sys/kernel/osrelease; then
if ! rpm -q --quiet "rear" ; then
dnf install -y "rear"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure rear is installed
package:
name: rear
state: present
tags:
- CCE-83503-3
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_rear_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_rear
class install_rear {
package { 'rear':
ensure => 'installed',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
package --add=rear
Remediation script: (show)
[[packages]]
name = "rear"
version = "*"
|
Updating Software
[ref]groupThe dnf command line tool is used to install and
update software packages. The system also provides a graphical
software update tool in the System menu, in the Administration submenu,
called Software Update.
Red Hat Enterprise Linux 9 systems contain an installed software catalog called
the RPM database, which records metadata of installed packages. Consistently using
dnf or the graphical Software Update for all software installation
allows for insight into the current inventory of installed software on the system.
|
contains 6 rules |
Configure dnf-automatic to Install Only Security Updates
[ref]ruleTo configure dnf-automatic to install only security updates
automatically, set upgrade_type to security under
[commands] section in /etc/dnf/automatic.conf . Rationale:By default, dnf-automatic installs all available updates.
Reducing the amount of updated packages only to updates that were
issued as a part of a security advisory increases the system stability. Remediation Shell script: (show)
found=false
# set value in all files if they contain section or key
for f in $(echo -n "/etc/dnf/automatic.conf"); do
if [ ! -e "$f" ]; then
continue
fi
# find key in section and change value
if grep -qzosP "[[:space:]]*\[commands\]([^\n\[]*\n+)+?[[:space:]]*upgrade_type" "$f"; then
sed -i "s/upgrade_type[^(\n)]*/upgrade_type = security/" "$f"
found=true
# find section and add key = value to it
elif grep -qs "[[:space:]]*\[commands\]" "$f"; then
sed -i "/[[:space:]]*commands/a upgrade_type = security" "$f"
found=true
fi
done
# if section not in any file, append section with key = value to FIRST file in files parameter
if ! $found ; then
file=$(echo "/etc/dnf/automatic.conf" | cut -f1 -d' ')
mkdir -p "$(dirname "$file")"
echo -e "[commands]\nupgrade_type = security" >> "$file"
fi
|
Ensure gpgcheck Enabled In Main dnf Configuration
[ref]ruleThe gpgcheck option controls whether
RPM packages' signatures are always checked prior to installation.
To configure dnf to check package signatures before installing
them, ensure the following line appears in /etc/dnf/dnf.conf in
the [main] section:
gpgcheck=1 Rationale:Changes to any software components can have significant effects on the
overall security of the operating system. This requirement ensures the
software has not been tampered with and that it has been provided by a
trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system
components must be signed with a certificate recognized and approved by the
organization.
Verifying the authenticity of the software prior to installation
validates the integrity of the patch or upgrade received from a vendor.
This ensures the software has not been tampered with and that it has been
provided by a trusted vendor. Self-signed certificates are disallowed by
this requirement. Certificates used to verify the software must be from an
approved Certificate Authority (CA). Identifiers:
CCE-83457-2 References:
BP28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, Req-6.2, SRG-OS-000366-GPOS-00153, SRG-OS-000366-VMM-001430, SRG-OS-000370-VMM-001460, SRG-OS-000404-VMM-001650 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q yum; then
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/dnf/dnf.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^gpgcheck")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^gpgcheck\\>" "/etc/dnf/dnf.conf"; then
"${sed_command[@]}" "s/^gpgcheck\\>.*/$formatted_output/gi" "/etc/dnf/dnf.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83457-2"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/dnf/dnf.conf" >> "/etc/dnf/dnf.conf"
printf '%s\n' "$formatted_output" >> "/etc/dnf/dnf.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83457-2
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- configure_strategy
- ensure_gpgcheck_globally_activated
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- name: Ensure GPG check is globally activated
ini_file:
dest: /etc/dnf/dnf.conf
section: main
option: gpgcheck
value: 1
no_extra_spaces: true
create: false
when: '"yum" in ansible_facts.packages'
tags:
- CCE-83457-2
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- configure_strategy
- ensure_gpgcheck_globally_activated
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
|
Ensure gpgcheck Enabled for Local Packages
[ref]rulednf should be configured to verify the signature(s) of local packages
prior to installation. To configure dnf to verify signatures of local
packages, set the localpkg_gpgcheck to 1 in /etc/dnf/dnf.conf . Rationale:Changes to any software components can have significant effects to the overall security
of the operating system. This requirement ensures the software has not been tampered and
has been provided by a trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system components must
be signed with a certificate recognized and approved by the organization. Identifiers:
CCE-83463-0 References:
BP28(R15), 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-11(a), CM-11(b), CM-6(a), CM-5(3), SA-12, SA-12(10), PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, SRG-OS-000366-GPOS-00153, SRG-OS-000366-VMM-001430, SRG-OS-000370-VMM-001460, SRG-OS-000404-VMM-001650 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q yum; then
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/dnf/dnf.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^localpkg_gpgcheck")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^localpkg_gpgcheck\\>" "/etc/dnf/dnf.conf"; then
"${sed_command[@]}" "s/^localpkg_gpgcheck\\>.*/$formatted_output/gi" "/etc/dnf/dnf.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83463-0"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/dnf/dnf.conf" >> "/etc/dnf/dnf.conf"
printf '%s\n' "$formatted_output" >> "/etc/dnf/dnf.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83463-0
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- ensure_gpgcheck_local_packages
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
- name: Ensure GPG check Enabled for Local Packages (Yum)
ini_file:
dest: /etc/dnf/dnf.conf
section: main
option: localpkg_gpgcheck
value: 1
no_extra_spaces: true
create: true
when: '"yum" in ansible_facts.packages'
tags:
- CCE-83463-0
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- ensure_gpgcheck_local_packages
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
|
Ensure gpgcheck Enabled for All dnf Package Repositories
[ref]ruleTo ensure signature checking is not disabled for
any repos, remove any lines from files in /etc/yum.repos.d of the form:
gpgcheck=0 Rationale:Verifying the authenticity of the software prior to installation validates
the integrity of the patch or upgrade received from a vendor. This ensures
the software has not been tampered with and that it has been provided by a
trusted vendor. Self-signed certificates are disallowed by this
requirement. Certificates used to verify the software must be from an
approved Certificate Authority (CA)." Identifiers:
CCE-83464-8 References:
BP28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, Req-6.2, SRG-OS-000366-GPOS-00153, SRG-OS-000366-VMM-001430, SRG-OS-000370-VMM-001460, SRG-OS-000404-VMM-001650 Remediation Shell script: (show)
sed -i 's/gpgcheck\s*=.*/gpgcheck=1/g' /etc/yum.repos.d/*
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Strategy: | enable |
---|
- name: Grep for dnf repo section names
shell: |
set -o pipefail
grep -HEr '^\[.+\]' -r /etc/yum.repos.d/
register: repo_grep_results
ignore_errors: true
changed_when: false
tags:
- CCE-83464-8
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- enable_strategy
- ensure_gpgcheck_never_disabled
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- name: Set gpgcheck=1 for each dnf repo
ini_file:
path: '{{ item[0] }}'
section: '{{ item[1] }}'
option: gpgcheck
value: '1'
no_extra_spaces: true
loop: '{{ repo_grep_results.stdout | regex_findall( ''(.+\.repo):\[(.+)\]\n?'' )
}}'
tags:
- CCE-83464-8
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- enable_strategy
- ensure_gpgcheck_never_disabled
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
|
Ensure Red Hat GPG Key Installed
[ref]ruleTo ensure the system can cryptographically verify base software packages
come from Red Hat (and to connect to the Red Hat Network to receive them),
the Red Hat GPG key must properly be installed. To install the Red Hat GPG
key, run:
$ sudo subscription-manager register
If the system is not connected to the Internet or an RHN Satellite, then
install the Red Hat GPG key from trusted media such as the Red Hat
installation CD-ROM or DVD. Assuming the disc is mounted in
/media/cdrom , use the following command as the root user to import
it into the keyring:
$ sudo rpm --import /media/cdrom/RPM-GPG-KEY
Alternatively, the key may be pre-loaded during the RHEL installation. In
such cases, the key can be installed by running the following command:
sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release Rationale:Changes to software components can have significant effects on the overall
security of the operating system. This requirement ensures the software has
not been tampered with and that it has been provided by a trusted vendor.
The Red Hat GPG key is necessary to cryptographically verify packages are
from Red Hat. Identifiers:
CCE-84180-9 References:
BP28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CIP-003-8 R4.2, CIP-003-8 R6, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), PR.DS-6, PR.DS-8, PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, Req-6.2, SRG-OS-000366-GPOS-00153, SRG-OS-000366-VMM-001430, SRG-OS-000370-VMM-001460, SRG-OS-000404-VMM-001650 Remediation Shell script: (show)
# The two fingerprints below are retrieved from https://access.redhat.com/security/team/key
readonly REDHAT_RELEASE_FINGERPRINT="567E347AD0044ADE55BA8A5F199E2F91FD431D51"
readonly REDHAT_AUXILIARY_FINGERPRINT="7E4624258C406535D56D6F135054E4A45A6340B3"
# Location of the key we would like to import (once it's integrity verified)
readonly REDHAT_RELEASE_KEY="/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release"
RPM_GPG_DIR_PERMS=$(stat -c %a "$(dirname "$REDHAT_RELEASE_KEY")")
# Verify /etc/pki/rpm-gpg directory permissions are safe
if [ "${RPM_GPG_DIR_PERMS}" -le "755" ]
then
# If they are safe, try to obtain fingerprints from the key file
# (to ensure there won't be e.g. CRC error).
readarray -t GPG_OUT < <(gpg --with-fingerprint --with-colons "$REDHAT_RELEASE_KEY" | grep "^fpr" | cut -d ":" -f 10)
GPG_RESULT=$?
# No CRC error, safe to proceed
if [ "${GPG_RESULT}" -eq "0" ]
then
echo "${GPG_OUT[*]}" | grep -vE "${REDHAT_RELEASE_FINGERPRINT}|${REDHAT_AUXILIARY_FINGERPRINT}" || {
# If $REDHAT_RELEASE_KEY file doesn't contain any keys with unknown fingerprint, import it
rpm --import "${REDHAT_RELEASE_KEY}"
}
fi
fi
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read permission of GPG key directory
stat:
path: /etc/pki/rpm-gpg/
register: gpg_key_directory_permission
check_mode: false
tags:
- CCE-84180-9
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- ensure_redhat_gpgkey_installed
- high_severity
- medium_complexity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- name: Read signatures in GPG key
command: gpg --show-keys --with-fingerprint --with-colons "/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release"
args:
warn: false
changed_when: false
register: gpg_fingerprints
check_mode: false
tags:
- CCE-84180-9
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- ensure_redhat_gpgkey_installed
- high_severity
- medium_complexity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- name: Set Fact - Installed GPG Fingerprints
set_fact:
gpg_installed_fingerprints: |-
{{ gpg_fingerprints.stdout | regex_findall('^pub.*
(?:^fpr[:]*)([0-9A-Fa-f]*)', '\1') | list }}
tags:
- CCE-84180-9
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- ensure_redhat_gpgkey_installed
- high_severity
- medium_complexity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- name: Set Fact - Valid fingerprints
set_fact:
gpg_valid_fingerprints: ("567E347AD0044ADE55BA8A5F199E2F91FD431D51" "7E4624258C406535D56D6F135054E4A45A6340B3")
tags:
- CCE-84180-9
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- ensure_redhat_gpgkey_installed
- high_severity
- medium_complexity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- name: Import RedHat GPG key
rpm_key:
state: present
key: /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release
when:
- gpg_key_directory_permission.stat.mode <= '0755'
- (gpg_installed_fingerprints | difference(gpg_valid_fingerprints)) | length ==
0
- gpg_installed_fingerprints | length > 0
- ansible_distribution == "RedHat"
tags:
- CCE-84180-9
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- ensure_redhat_gpgkey_installed
- high_severity
- medium_complexity
- medium_disruption
- no_reboot_needed
- restrict_strategy
|
Ensure Software Patches Installed
[ref]rule
NOTE: U.S. Defense systems are required to be patched within 30 days or sooner as local policy
dictates.
Warning:
The OVAL feed of Red Hat Enterprise Linux 9 is not a XML file, which may not be understood by all scanners. Rationale:Installing software updates is a fundamental mitigation against
the exploitation of publicly-known vulnerabilities. If the most
recent security patches and updates are not installed, unauthorized
users may take advantage of weaknesses in the unpatched software. The
lack of prompt attention to patching could result in a system compromise. Identifiers:
CCE-84185-8 References:
BP28(R08), 18, 20, 4, 5.10.4.1, APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02, CCI-000366, CCI-001227, 4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9, A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3, SI-2(5), SI-2(c), CM-6(a), ID.RA-1, PR.IP-12, FMT_MOF_EXT.1, Req-6.2, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | true |
---|
Strategy: | patch |
---|
yum -y update
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | true |
---|
Strategy: | patch |
---|
- name: Security patches are up to date
package:
name: '*'
state: latest
tags:
- CCE-84185-8
- CJIS-5.10.4.1
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-2(5)
- NIST-800-53-SI-2(c)
- PCI-DSS-Req-6.2
- high_disruption
- low_complexity
- medium_severity
- patch_strategy
- reboot_required
- security_patches_up_to_date
- skip_ansible_lint
|
Account and Access Control
[ref]groupIn traditional Unix security, if an attacker gains
shell access to a certain login account, they can perform any action
or access any file to which that account has access. Therefore,
making it more difficult for unauthorized people to gain shell
access to accounts, particularly to privileged accounts, is a
necessary part of securing a system. This section introduces
mechanisms for restricting access to accounts under
Red Hat Enterprise Linux 9. |
contains 15 rules |
Protect Accounts by Configuring PAM
[ref]groupPAM, or Pluggable Authentication Modules, is a system
which implements modular authentication for Linux programs. PAM provides
a flexible and configurable architecture for authentication, and it should be configured
to minimize exposure to unnecessary risk. This section contains
guidance on how to accomplish that.
PAM is implemented as a set of shared objects which are
loaded and invoked whenever an application wishes to authenticate a
user. Typically, the application must be running as root in order
to take advantage of PAM, because PAM's modules often need to be able
to access sensitive stores of account information, such as /etc/shadow.
Traditional privileged network listeners
(e.g. sshd) or SUID programs (e.g. sudo) already meet this
requirement. An SUID root application, userhelper, is provided so
that programs which are not SUID or privileged themselves can still
take advantage of PAM.
PAM looks in the directory /etc/pam.d for
application-specific configuration information. For instance, if
the program login attempts to authenticate a user, then PAM's
libraries follow the instructions in the file /etc/pam.d/login
to determine what actions should be taken.
One very important file in /etc/pam.d is
/etc/pam.d/system-auth . This file, which is included by
many other PAM configuration files, defines 'default' system authentication
measures. Modifying this file is a good way to make far-reaching
authentication changes, for instance when implementing a
centralized authentication service. Warning:
Be careful when making changes to PAM's configuration files.
The syntax for these files is complex, and modifications can
have unexpected consequences. The default configurations shipped
with applications should be sufficient for most users. |
contains 6 rules |
Set Lockouts for Failed Password Attempts
[ref]groupThe pam_faillock PAM module provides the capability to
lock out user accounts after a number of failed login attempts. Its
documentation is available in
/usr/share/doc/pam-VERSION/txts/README.pam_faillock .
Warning:
Locking out user accounts presents the
risk of a denial-of-service attack. The lockout policy
must weigh whether the risk of such a
denial-of-service attack outweighs the benefits of thwarting
password guessing attacks. |
contains 4 rules |
Lock Accounts After Failed Password Attempts
[ref]ruleThis rule configures the system to lock out accounts after a number of incorrect login attempts
using pam_faillock.so .
pam_faillock.so module requires multiple entries in pam files. These entries must be carefully
defined to work as expected. In order to avoid any errors when manually editing these files,
it is recommended to use the appropriate tools, such as authselect or authconfig ,
depending on the OS version. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. Rationale:Locking out user accounts after a number of incorrect attempts prevents direct password
guessing attacks. In combination with the silent option, user enumeration attacks
are also mitigated. Identifiers:
CCE-83587-6 References:
BP28(R18), 1, 12, 15, 16, 5.5.3, DSS05.04, DSS05.10, DSS06.10, 3.1.8, CCI-000044, CCI-002236, CCI-002237, CCI-002238, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(a), PR.AC-7, FIA_AFL.1, Req-8.1.6, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005, SRG-OS-000021-VMM-000050 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_accounts_passwords_pam_faillock_deny='3'
if [ -f /usr/bin/authselect ]; then
if authselect check; then
authselect enable-feature with-faillock
authselect apply-changes
else
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
false
fi
else
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix.so.*/i auth required pam_faillock.so preauth silent' "$pam_file"
sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix.so.*/a auth required pam_faillock.so authfail' "$pam_file"
sed -i --follow-symlinks '/^account.*required.*pam_unix.so.*/i account required pam_faillock.so' "$pam_file"
fi
sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock.so)/\1required \3/g' "$pam_file"
done
fi
FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ]; then
regex="^\s*deny\s*="
line="deny = $var_accounts_passwords_pam_faillock_deny"
if ! grep -q $regex $FAILLOCK_CONF; then
echo $line >> $FAILLOCK_CONF
else
sed -i --follow-symlinks 's/^\s*\(deny\s*=\s*\)\([0-9]\+\)/\1'"$var_accounts_passwords_pam_faillock_deny"'/g' $FAILLOCK_CONF
fi
else
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
if ! grep -qE '^\s*auth.*pam_faillock.so (preauth|authfail).*deny' "$pam_file"; then
sed -i --follow-symlinks '/^auth.*required.*pam_faillock.so.*preauth.*silent.*/ s/$/ deny='"$var_accounts_passwords_pam_faillock_deny"'/' "$pam_file"
sed -i --follow-symlinks '/^auth.*required.*pam_faillock.so.*authfail.*/ s/$/ deny='"$var_accounts_passwords_pam_faillock_deny"'/' "$pam_file"
else
sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock.so.*preauth.*silent.*\)\('"deny"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_deny"'\3/' "$pam_file"
sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock.so.*authfail.*\)\('"deny"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_deny"'\3/' "$pam_file"
fi
done
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83587-6
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- accounts_passwords_pam_faillock_deny
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Lock Accounts After Failed Password Attempts - Check if system relies on authselect
tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83587-6
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- accounts_passwords_pam_faillock_deny
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Lock Accounts After Failed Password Attempts - Remediation where authselect
tool is present
block:
- name: Lock Accounts After Failed Password Attempts - Check integrity of authselect
current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
ignore_errors: true
- name: Lock Accounts After Failed Password Attempts - Informative message based
on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd is success
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile was
not selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect tool
is available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Lock Accounts After Failed Password Attempts - Get authselect current
features
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Lock Accounts After Failed Password Attempts - Ensure with-faillock feature
is enabled using authselect tool
ansible.builtin.command:
cmd: authselect enable-feature with-faillock
register: result_authselect_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("with-faillock")
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CCE-83587-6
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- accounts_passwords_pam_faillock_deny
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Lock Accounts After Failed Password Attempts - Remediation where authselect
tool is not present
block:
- name: Lock Accounts After Failed Password Attempts - Check if pam_faillock.so
is already enabled
ansible.builtin.lineinfile:
path: /etc/pam.d/system-auth
regexp: .*auth.*pam_faillock.so (preauth|authfail)
state: absent
check_mode: true
changed_when: false
register: result_pam_faillock_is_enabled
- name: Lock Accounts After Failed Password Attempts - Enable pam_faillock.so
preauth editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: auth required pam_faillock.so preauth
insertbefore: ^auth.*sufficient.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
- name: Lock Accounts After Failed Password Attempts - Enable pam_faillock.so
authfail editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: auth required pam_faillock.so authfail
insertafter: ^auth.*sufficient.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
- name: Lock Accounts After Failed Password Attempts - Enable pam_faillock.so
account section editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: account required pam_faillock.so
insertbefore: ^account.*required.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
when:
- '"pam" in ansible_facts.packages'
- not result_authselect_present.stat.exists
tags:
- CCE-83587-6
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- accounts_passwords_pam_faillock_deny
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_passwords_pam_faillock_deny # promote to variable
set_fact:
var_accounts_passwords_pam_faillock_deny: !!str 3
tags:
- always
- name: Lock Accounts After Failed Password Attempts - Check the presence of /etc/security/faillock.conf
file
ansible.builtin.stat:
path: /etc/security/faillock.conf
register: result_faillock_conf_check
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83587-6
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- accounts_passwords_pam_faillock_deny
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Lock Accounts After Failed Password Attempts - Ensure the pam_faillock.so
deny parameter in /etc/security/faillock.conf
ansible.builtin.lineinfile:
path: /etc/security/faillock.conf
regexp: ^\s*deny\s*=
line: deny = {{ var_accounts_passwords_pam_faillock_deny }}
state: present
when:
- '"pam" in ansible_facts.packages'
- result_faillock_conf_check.stat.exists
tags:
- CCE-83587-6
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- accounts_passwords_pam_faillock_deny
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Lock Accounts After Failed Password Attempts - Ensure the pam_faillock.so
deny parameter in PAM files
block:
- name: Lock Accounts After Failed Password Attempts - Check if pam_faillock.so
deny parameter is already enabled in pam files
ansible.builtin.lineinfile:
path: /etc/pam.d/system-auth
regexp: .*auth.*pam_faillock.so (preauth|authfail).*deny
state: absent
check_mode: true
changed_when: false
register: result_pam_faillock_deny_parameter_is_present
- name: Lock Accounts After Failed Password Attempts - Ensure the inclusion of
pam_faillock.so preauth deny parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
line: \1required\3 deny={{ var_accounts_passwords_pam_faillock_deny }}
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_deny_parameter_is_present.found == 0
- name: Lock Accounts After Failed Password Attempts - Ensure the inclusion of
pam_faillock.so authfail deny parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
line: \1required\3 deny={{ var_accounts_passwords_pam_faillock_deny }}
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_deny_parameter_is_present.found == 0
- name: Lock Accounts After Failed Password Attempts - Ensure the desired value
for pam_faillock.so preauth deny parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)(deny)=[0-9]+(.*)
line: \1required\3\4={{ var_accounts_passwords_pam_faillock_deny }}\5
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_deny_parameter_is_present.found > 0
- name: Lock Accounts After Failed Password Attempts - Ensure the desired value
for pam_faillock.so authfail deny parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)(deny)=[0-9]+(.*)
line: \1required\3\4={{ var_accounts_passwords_pam_faillock_deny }}\5
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_deny_parameter_is_present.found > 0
when:
- '"pam" in ansible_facts.packages'
- not result_faillock_conf_check.stat.exists
tags:
- CCE-83587-6
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- accounts_passwords_pam_faillock_deny
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Configure the root Account for Failed Password Attempts
[ref]ruleThis rule configures the system to lock out the root account after a number of
incorrect login attempts using pam_faillock.so .
pam_faillock.so module requires multiple entries in pam files. These entries must be carefully
defined to work as expected. In order to avoid any errors when manually editing these files,
it is recommended to use the appropriate tools, such as authselect or authconfig ,
depending on the OS version. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. Rationale:By limiting the number of failed logon attempts, the risk of unauthorized system access via
user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking
the account. Identifiers:
CCE-83589-2 References:
BP28(R18), 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, CCI-002238, CCI-000044, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(b), IA-5(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
if [ -f /usr/bin/authselect ]; then
if authselect check; then
authselect enable-feature with-faillock
authselect apply-changes
else
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
false
fi
else
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix.so.*/i auth required pam_faillock.so preauth silent' "$pam_file"
sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix.so.*/a auth required pam_faillock.so authfail' "$pam_file"
sed -i --follow-symlinks '/^account.*required.*pam_unix.so.*/i account required pam_faillock.so' "$pam_file"
fi
sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock.so)/\1required \3/g' "$pam_file"
done
fi
FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ]; then
regex="^\s*even_deny_root"
line="even_deny_root"
if ! grep -q $regex $FAILLOCK_CONF; then
echo $line >> $FAILLOCK_CONF
fi
else
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
if ! grep -qE '^\s*auth.*pam_faillock.so (preauth|authfail).*even_deny_root' "$pam_file"; then
sed -i --follow-symlinks '/^auth.*required.*pam_faillock.so.*preauth.*silent.*/ s/$/ even_deny_root/' "$pam_file"
sed -i --follow-symlinks '/^auth.*required.*pam_faillock.so.*authfail.*/ s/$/ even_deny_root/' "$pam_file"
fi
done
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83589-2
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- accounts_passwords_pam_faillock_deny_root
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure the root Account for Failed Password Attempts - Check if system
relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83589-2
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- accounts_passwords_pam_faillock_deny_root
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure the root Account for Failed Password Attempts - Remediation where
authselect tool is present
block:
- name: Configure the root Account for Failed Password Attempts - Check integrity
of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
ignore_errors: true
- name: Configure the root Account for Failed Password Attempts - Informative
message based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd is success
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile was
not selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect tool
is available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Configure the root Account for Failed Password Attempts - Get authselect
current features
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Configure the root Account for Failed Password Attempts - Ensure with-faillock
feature is enabled using authselect tool
ansible.builtin.command:
cmd: authselect enable-feature with-faillock
register: result_authselect_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("with-faillock")
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CCE-83589-2
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- accounts_passwords_pam_faillock_deny_root
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure the root Account for Failed Password Attempts - Remediation where
authselect tool is not present
block:
- name: Configure the root Account for Failed Password Attempts - Check if pam_faillock.so
is already enabled
ansible.builtin.lineinfile:
path: /etc/pam.d/system-auth
regexp: .*auth.*pam_faillock.so (preauth|authfail)
state: absent
check_mode: true
changed_when: false
register: result_pam_faillock_is_enabled
- name: Configure the root Account for Failed Password Attempts - Enable pam_faillock.so
preauth editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: auth required pam_faillock.so preauth
insertbefore: ^auth.*sufficient.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
- name: Configure the root Account for Failed Password Attempts - Enable pam_faillock.so
authfail editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: auth required pam_faillock.so authfail
insertafter: ^auth.*sufficient.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
- name: Configure the root Account for Failed Password Attempts - Enable pam_faillock.so
account section editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: account required pam_faillock.so
insertbefore: ^account.*required.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
when:
- '"pam" in ansible_facts.packages'
- not result_authselect_present.stat.exists
tags:
- CCE-83589-2
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- accounts_passwords_pam_faillock_deny_root
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure the root Account for Failed Password Attempts - Check the presence
of /etc/security/faillock.conf file
ansible.builtin.stat:
path: /etc/security/faillock.conf
register: result_faillock_conf_check
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83589-2
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- accounts_passwords_pam_faillock_deny_root
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure the root Account for Failed Password Attempts - Ensure the pam_faillock.so
even_deny_root parameter in /etc/security/faillock.conf
ansible.builtin.lineinfile:
path: /etc/security/faillock.conf
regexp: ^\s*even_deny_root
line: even_deny_root
state: present
when:
- '"pam" in ansible_facts.packages'
- result_faillock_conf_check.stat.exists
tags:
- CCE-83589-2
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- accounts_passwords_pam_faillock_deny_root
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure the root Account for Failed Password Attempts - Ensure the pam_faillock.so
even_deny_root parameter in PAM files
block:
- name: Configure the root Account for Failed Password Attempts - Check if pam_faillock.so
even_deny_root parameter is already enabled in pam files
ansible.builtin.lineinfile:
path: /etc/pam.d/system-auth
regexp: .*auth.*pam_faillock.so (preauth|authfail).*even_deny_root
state: absent
check_mode: true
changed_when: false
register: result_pam_faillock_even_deny_root_parameter_is_present
- name: Configure the root Account for Failed Password Attempts - Ensure the inclusion
of pam_faillock.so preauth even_deny_root parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
line: \1required\3 even_deny_root
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_even_deny_root_parameter_is_present.found == 0
- name: Configure the root Account for Failed Password Attempts - Ensure the inclusion
of pam_faillock.so authfail even_deny_root parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
line: \1required\3 even_deny_root
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_even_deny_root_parameter_is_present.found == 0
when:
- '"pam" in ansible_facts.packages'
- not result_faillock_conf_check.stat.exists
tags:
- CCE-83589-2
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- accounts_passwords_pam_faillock_deny_root
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Interval For Counting Failed Password Attempts
[ref]ruleUtilizing pam_faillock.so , the fail_interval directive configures the system
to lock out an account after a number of incorrect login attempts within a specified time
period. First make sure the feature is enabled using the following command:
Then edit the /etc/security/faillock.conf file as follows:
- add, uncomment or edit the following line:
fail_interval = 900 - add or uncomment the following line:
silent
Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. Rationale:By limiting the number of failed logon attempts the risk of unauthorized system
access via user password guessing, otherwise known as brute-forcing, is reduced.
Limits are imposed by locking the account. Identifiers:
CCE-83583-5 References:
BP28(R18), 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, CCI-000044, CCI-002236, CCI-002237, CCI-002238, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(a), PR.AC-7, FIA_AFL.1, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005, SRG-OS-000021-VMM-000050 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_accounts_passwords_pam_faillock_fail_interval='900'
if [ -f /usr/bin/authselect ]; then
if authselect check; then
authselect enable-feature with-faillock
authselect apply-changes
else
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
false
fi
else
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix.so.*/i auth required pam_faillock.so preauth silent' "$pam_file"
sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix.so.*/a auth required pam_faillock.so authfail' "$pam_file"
sed -i --follow-symlinks '/^account.*required.*pam_unix.so.*/i account required pam_faillock.so' "$pam_file"
fi
sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock.so)/\1required \3/g' "$pam_file"
done
fi
FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ]; then
regex="^\s*fail_interval\s*="
line="fail_interval = $var_accounts_passwords_pam_faillock_fail_interval"
if ! grep -q $regex $FAILLOCK_CONF; then
echo $line >> $FAILLOCK_CONF
else
sed -i --follow-symlinks 's/^\s*\(fail_interval\s*=\s*\)\([0-9]\+\)/\1'"$var_accounts_passwords_pam_faillock_fail_interval"'/g' $FAILLOCK_CONF
fi
else
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
if ! grep -qE '^\s*auth.*pam_faillock.so (preauth|authfail).*fail_interval' "$pam_file"; then
sed -i --follow-symlinks '/^auth.*required.*pam_faillock.so.*preauth.*silent.*/ s/$/ fail_interval='"$var_accounts_passwords_pam_faillock_fail_interval"'/' "$pam_file"
sed -i --follow-symlinks '/^auth.*required.*pam_faillock.so.*authfail.*/ s/$/ fail_interval='"$var_accounts_passwords_pam_faillock_fail_interval"'/' "$pam_file"
else
sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock.so.*preauth.*silent.*\)\('"fail_interval"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_fail_interval"'\3/' "$pam_file"
sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock.so.*authfail.*\)\('"fail_interval"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_fail_interval"'\3/' "$pam_file"
fi
done
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83583-5
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- accounts_passwords_pam_faillock_interval
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Interval For Counting Failed Password Attempts - Check if system relies
on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83583-5
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- accounts_passwords_pam_faillock_interval
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Interval For Counting Failed Password Attempts - Remediation where authselect
tool is present
block:
- name: Set Interval For Counting Failed Password Attempts - Check integrity of
authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
ignore_errors: true
- name: Set Interval For Counting Failed Password Attempts - Informative message
based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd is success
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile was
not selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect tool
is available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Set Interval For Counting Failed Password Attempts - Get authselect current
features
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Set Interval For Counting Failed Password Attempts - Ensure with-faillock
feature is enabled using authselect tool
ansible.builtin.command:
cmd: authselect enable-feature with-faillock
register: result_authselect_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("with-faillock")
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CCE-83583-5
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- accounts_passwords_pam_faillock_interval
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Interval For Counting Failed Password Attempts - Remediation where authselect
tool is not present
block:
- name: Set Interval For Counting Failed Password Attempts - Check if pam_faillock.so
is already enabled
ansible.builtin.lineinfile:
path: /etc/pam.d/system-auth
regexp: .*auth.*pam_faillock.so (preauth|authfail)
state: absent
check_mode: true
changed_when: false
register: result_pam_faillock_is_enabled
- name: Set Interval For Counting Failed Password Attempts - Enable pam_faillock.so
preauth editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: auth required pam_faillock.so preauth
insertbefore: ^auth.*sufficient.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
- name: Set Interval For Counting Failed Password Attempts - Enable pam_faillock.so
authfail editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: auth required pam_faillock.so authfail
insertafter: ^auth.*sufficient.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
- name: Set Interval For Counting Failed Password Attempts - Enable pam_faillock.so
account section editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: account required pam_faillock.so
insertbefore: ^account.*required.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
when:
- '"pam" in ansible_facts.packages'
- not result_authselect_present.stat.exists
tags:
- CCE-83583-5
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- accounts_passwords_pam_faillock_interval
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_passwords_pam_faillock_fail_interval # promote to variable
set_fact:
var_accounts_passwords_pam_faillock_fail_interval: !!str 900
tags:
- always
- name: Set Interval For Counting Failed Password Attempts - Check the presence of
/etc/security/faillock.conf file
ansible.builtin.stat:
path: /etc/security/faillock.conf
register: result_faillock_conf_check
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83583-5
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- accounts_passwords_pam_faillock_interval
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Interval For Counting Failed Password Attempts - Ensure the pam_faillock.so
fail_interval parameter in /etc/security/faillock.conf
ansible.builtin.lineinfile:
path: /etc/security/faillock.conf
regexp: ^\s*fail_interval\s*=
line: fail_interval = {{ var_accounts_passwords_pam_faillock_fail_interval }}
state: present
when:
- '"pam" in ansible_facts.packages'
- result_faillock_conf_check.stat.exists
tags:
- CCE-83583-5
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- accounts_passwords_pam_faillock_interval
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Interval For Counting Failed Password Attempts - Ensure the pam_faillock.so
fail_interval parameter in PAM files
block:
- name: Set Interval For Counting Failed Password Attempts - Check if pam_faillock.so
fail_interval parameter is already enabled in pam files
ansible.builtin.lineinfile:
path: /etc/pam.d/system-auth
regexp: .*auth.*pam_faillock.so (preauth|authfail).*fail_interval
state: absent
check_mode: true
changed_when: false
register: result_pam_faillock_fail_interval_parameter_is_present
- name: Set Interval For Counting Failed Password Attempts - Ensure the inclusion
of pam_faillock.so preauth fail_interval parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
line: \1required\3 fail_interval={{ var_accounts_passwords_pam_faillock_fail_interval
}}
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_fail_interval_parameter_is_present.found == 0
- name: Set Interval For Counting Failed Password Attempts - Ensure the inclusion
of pam_faillock.so authfail fail_interval parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
line: \1required\3 fail_interval={{ var_accounts_passwords_pam_faillock_fail_interval
}}
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_fail_interval_parameter_is_present.found == 0
- name: Set Interval For Counting Failed Password Attempts - Ensure the desired
value for pam_faillock.so preauth fail_interval parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)(fail_interval)=[0-9]+(.*)
line: \1required\3\4={{ var_accounts_passwords_pam_faillock_fail_interval
}}\5
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_fail_interval_parameter_is_present.found > 0
- name: Set Interval For Counting Failed Password Attempts - Ensure the desired
value for pam_faillock.so authfail fail_interval parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)(fail_interval)=[0-9]+(.*)
line: \1required\3\4={{ var_accounts_passwords_pam_faillock_fail_interval
}}\5
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_fail_interval_parameter_is_present.found > 0
when:
- '"pam" in ansible_facts.packages'
- not result_faillock_conf_check.stat.exists
tags:
- CCE-83583-5
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- accounts_passwords_pam_faillock_interval
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Lockout Time for Failed Password Attempts
[ref]ruleThis rule configures the system to lock out accounts during a specified time period after a
number of incorrect login attempts using pam_faillock.so .
pam_faillock.so module requires multiple entries in pam files. These entries must be carefully
defined to work as expected. In order to avoid any errors when manually editing these files,
it is recommended to use the appropriate tools, such as authselect or authconfig ,
depending on the OS version. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. Rationale:Locking out user accounts after a number of incorrect attempts prevents direct password
guessing attacks. Ensuring that an administrator is involved in unlocking locked accounts
draws appropriate attention to such situations. Identifiers:
CCE-83588-4 References:
BP28(R18), 1, 12, 15, 16, 5.5.3, DSS05.04, DSS05.10, DSS06.10, 3.1.8, CCI-000044, CCI-002236, CCI-002237, CCI-002238, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(b), PR.AC-7, FIA_AFL.1, Req-8.1.7, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005, SRG-OS-000329-VMM-001180 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_accounts_passwords_pam_faillock_unlock_time='0'
if [ -f /usr/bin/authselect ]; then
if authselect check; then
authselect enable-feature with-faillock
authselect apply-changes
else
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
false
fi
else
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix.so.*/i auth required pam_faillock.so preauth silent' "$pam_file"
sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix.so.*/a auth required pam_faillock.so authfail' "$pam_file"
sed -i --follow-symlinks '/^account.*required.*pam_unix.so.*/i account required pam_faillock.so' "$pam_file"
fi
sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock.so)/\1required \3/g' "$pam_file"
done
fi
FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ]; then
regex="^\s*unlock_time\s*="
line="unlock_time = $var_accounts_passwords_pam_faillock_unlock_time"
if ! grep -q $regex $FAILLOCK_CONF; then
echo $line >> $FAILLOCK_CONF
else
sed -i --follow-symlinks 's/^\s*\(unlock_time\s*=\s*\)\([0-9]\+\)/\1'"$var_accounts_passwords_pam_faillock_unlock_time"'/g' $FAILLOCK_CONF
fi
else
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
if ! grep -qE '^\s*auth.*pam_faillock.so (preauth|authfail).*unlock_time' "$pam_file"; then
sed -i --follow-symlinks '/^auth.*required.*pam_faillock.so.*preauth.*silent.*/ s/$/ unlock_time='"$var_accounts_passwords_pam_faillock_unlock_time"'/' "$pam_file"
sed -i --follow-symlinks '/^auth.*required.*pam_faillock.so.*authfail.*/ s/$/ unlock_time='"$var_accounts_passwords_pam_faillock_unlock_time"'/' "$pam_file"
else
sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock.so.*preauth.*silent.*\)\('"unlock_time"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_unlock_time"'\3/' "$pam_file"
sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock.so.*authfail.*\)\('"unlock_time"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_unlock_time"'\3/' "$pam_file"
fi
done
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83588-4
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- accounts_passwords_pam_faillock_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts - Check if system relies on
authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83588-4
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- accounts_passwords_pam_faillock_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts - Remediation where authselect
tool is present
block:
- name: Set Lockout Time for Failed Password Attempts - Check integrity of authselect
current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
ignore_errors: true
- name: Set Lockout Time for Failed Password Attempts - Informative message based
on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd is success
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile was
not selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect tool
is available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Set Lockout Time for Failed Password Attempts - Get authselect current
features
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Set Lockout Time for Failed Password Attempts - Ensure with-faillock feature
is enabled using authselect tool
ansible.builtin.command:
cmd: authselect enable-feature with-faillock
register: result_authselect_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("with-faillock")
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CCE-83588-4
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- accounts_passwords_pam_faillock_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts - Remediation where authselect
tool is not present
block:
- name: Set Lockout Time for Failed Password Attempts - Check if pam_faillock.so
is already enabled
ansible.builtin.lineinfile:
path: /etc/pam.d/system-auth
regexp: .*auth.*pam_faillock.so (preauth|authfail)
state: absent
check_mode: true
changed_when: false
register: result_pam_faillock_is_enabled
- name: Set Lockout Time for Failed Password Attempts - Enable pam_faillock.so
preauth editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: auth required pam_faillock.so preauth
insertbefore: ^auth.*sufficient.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
- name: Set Lockout Time for Failed Password Attempts - Enable pam_faillock.so
authfail editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: auth required pam_faillock.so authfail
insertafter: ^auth.*sufficient.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
- name: Set Lockout Time for Failed Password Attempts - Enable pam_faillock.so
account section editing PAM files
ansible.builtin.lineinfile:
path: '{{ item }}'
line: account required pam_faillock.so
insertbefore: ^account.*required.*pam_unix.so.*
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_is_enabled.found == 0
when:
- '"pam" in ansible_facts.packages'
- not result_authselect_present.stat.exists
tags:
- CCE-83588-4
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- accounts_passwords_pam_faillock_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_passwords_pam_faillock_unlock_time # promote to variable
set_fact:
var_accounts_passwords_pam_faillock_unlock_time: !!str 0
tags:
- always
- name: Set Lockout Time for Failed Password Attempts - Check the presence of /etc/security/faillock.conf
file
ansible.builtin.stat:
path: /etc/security/faillock.conf
register: result_faillock_conf_check
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83588-4
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- accounts_passwords_pam_faillock_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts - Ensure the pam_faillock.so
unlock_time parameter in /etc/security/faillock.conf
ansible.builtin.lineinfile:
path: /etc/security/faillock.conf
regexp: ^\s*unlock_time\s*=
line: unlock_time = {{ var_accounts_passwords_pam_faillock_unlock_time }}
state: present
when:
- '"pam" in ansible_facts.packages'
- result_faillock_conf_check.stat.exists
tags:
- CCE-83588-4
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- accounts_passwords_pam_faillock_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts - Ensure the pam_faillock.so
unlock_time parameter in PAM files
block:
- name: Set Lockout Time for Failed Password Attempts - Check if pam_faillock.so
unlock_time parameter is already enabled in pam files
ansible.builtin.lineinfile:
path: /etc/pam.d/system-auth
regexp: .*auth.*pam_faillock.so (preauth|authfail).*unlock_time
state: absent
check_mode: true
changed_when: false
register: result_pam_faillock_unlock_time_parameter_is_present
- name: Set Lockout Time for Failed Password Attempts - Ensure the inclusion of
pam_faillock.so preauth unlock_time parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
line: \1required\3 unlock_time={{ var_accounts_passwords_pam_faillock_unlock_time
}}
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_unlock_time_parameter_is_present.found == 0
- name: Set Lockout Time for Failed Password Attempts - Ensure the inclusion of
pam_faillock.so authfail unlock_time parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
line: \1required\3 unlock_time={{ var_accounts_passwords_pam_faillock_unlock_time
}}
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_unlock_time_parameter_is_present.found == 0
- name: Set Lockout Time for Failed Password Attempts - Ensure the desired value
for pam_faillock.so preauth unlock_time parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)(unlock_time)=[0-9]+(.*)
line: \1required\3\4={{ var_accounts_passwords_pam_faillock_unlock_time }}\5
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_unlock_time_parameter_is_present.found > 0
- name: Set Lockout Time for Failed Password Attempts - Ensure the desired value
for pam_faillock.so authfail unlock_time parameter in auth section
ansible.builtin.lineinfile:
path: '{{ item }}'
backrefs: true
regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)(unlock_time)=[0-9]+(.*)
line: \1required\3\4={{ var_accounts_passwords_pam_faillock_unlock_time }}\5
state: present
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- result_pam_faillock_unlock_time_parameter_is_present.found > 0
when:
- '"pam" in ansible_facts.packages'
- not result_faillock_conf_check.stat.exists
tags:
- CCE-83588-4
- CJIS-5.5.3
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- accounts_passwords_pam_faillock_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Quality Requirements
[ref]groupThe default pam_pwquality PAM module provides strength
checking for passwords. It performs a number of checks, such as
making sure passwords are not similar to dictionary words, are of
at least a certain length, are not the previous password reversed,
and are not simply a change of case from the previous password. It
can also require passwords to be in certain character classes. The
pam_pwquality module is the preferred way of configuring
password requirements.
The man pages pam_pwquality(8)
provide information on the capabilities and configuration of
each. |
contains 1 rule |
Set Password Quality Requirements with pam_pwquality
[ref]groupThe pam_pwquality PAM module can be configured to meet
requirements for a variety of policies.
For example, to configure pam_pwquality to require at least one uppercase
character, lowercase character, digit, and other (special)
character, make sure that pam_pwquality exists in /etc/pam.d/system-auth :
password requisite pam_pwquality.so try_first_pass local_users_only retry=3 authtok_type=
If no such line exists, add one as the first line of the password section in /etc/pam.d/system-auth .
Next, modify the settings in /etc/security/pwquality.conf to match the following:
difok = 4
minlen = 14
dcredit = -1
ucredit = -1
lcredit = -1
ocredit = -1
maxrepeat = 3
The arguments can be modified to ensure compliance with
your organization's security policy. Discussion of each parameter follows. |
contains 1 rule |
Ensure PAM Enforces Password Requirements - Minimum Length
[ref]ruleThe pam_pwquality module's minlen parameter controls requirements for
minimum characters required in a password. Add minlen=14
after pam_pwquality to set minimum password length requirements. Rationale:The shorter the password, the lower the number of possible combinations
that need to be tested before the password is compromised.
Password complexity, or strength, is a measure of the effectiveness of a
password in resisting attempts at guessing and brute-force attacks.
Password length is one factor of several that helps to determine strength
and how long it takes to crack a password. Use of more characters in a password
helps to exponentially increase the time and/or resources required to
compromose the password. Identifiers:
CCE-83579-3 References:
BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000205, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, FMT_MOF_EXT.1, Req-8.2.3, SRG-OS-000078-GPOS-00046, SRG-OS-000072-VMM-000390, SRG-OS-000078-VMM-000450 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_minlen='14'
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/security/pwquality.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^minlen")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_minlen"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^minlen\\>" "/etc/security/pwquality.conf"; then
"${sed_command[@]}" "s/^minlen\\>.*/$formatted_output/gi" "/etc/security/pwquality.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83579-3"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/security/pwquality.conf" >> "/etc/security/pwquality.conf"
printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83579-3
- CJIS-5.6.2.1.1
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(4)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_password_pam_minlen # promote to variable
set_fact:
var_password_pam_minlen: !!str 14
tags:
- always
- name: Ensure PAM variable minlen is set accordingly
lineinfile:
create: true
dest: /etc/security/pwquality.conf
regexp: ^#?\s*minlen
line: minlen = {{ var_password_pam_minlen }}
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83579-3
- CJIS-5.6.2.1.1
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(4)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure PAM Displays Last Logon/Access Notification
[ref]ruleTo configure the system to notify users of last logon/access
using pam_lastlog , add or correct the pam_lastlog
settings in
/etc/pam.d/postlogin to read as follows:
session required pam_lastlog.so showfailed
And make sure that the silent option is not set.Rationale:Users need to be aware of activity that occurs regarding
their account. Providing users with information regarding the number
of unsuccessful attempts that were made to login to their account
allows the user to determine if any unauthorized activity has occurred
and gives them an opportunity to notify administrators. Identifiers:
CCE-83560-3 References:
1, 12, 15, 16, 5.5.2, DSS05.04, DSS05.10, DSS06.10, CCI-000366, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0582, 0584, 05885, 0586, 0846, 0957, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-9(1), CM-6(a), PR.AC-7, Req-10.2.4, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
if [ -f /usr/bin/authselect ]; then
if authselect check; then
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# Standard profiles delivered with authselect should not be modified.
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
# Ensure a backup before changing the profile
authselect apply-changes -b --backup=before-pwhistory-hardening.backup
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
fi
# Include the desired configuration in the custom profile
CUSTOM_POSTLOGIN="/etc/authselect/$CURRENT_PROFILE/postlogin"
# The line should be included on the top of postlogin file
if [ "$(grep -c "^\s*session.*required.*pam_lastlog.so\s\+showfailed\s*$" $CUSTOM_POSTLOGIN)" -eq 0 ]; then
sed -i --follow-symlinks '0,/^session.*/s/^session.*/session required pam_lastlog.so showfailed\n&/' $CUSTOM_POSTLOGIN
fi
if grep -q "^\s*session.*required.*pam_lastlog.so.*silent.*" $CUSTOM_POSTLOGIN; then
# remove 'silent' option
sed -i --follow-symlinks 's/^\(session.*required.*pam_lastlog.so\).*/\1 showfailed/g' $CUSTOM_POSTLOGIN
fi
authselect apply-changes -b --backup=after-pwhistory-hardening.backup
else
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because the authselect profile is not intact.
It is not recommended to manually edit the PAM files when authselect is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
false
fi
else
if [ "$(grep -c "^\s*session.*required.*pam_lastlog.so\s\+showfailed\s*$" /etc/pam.d/postlogin)" -eq 0 ]; then
sed -i --follow-symlinks '0,/^session.*/s/^session.*/session required pam_lastlog.so showfailed\n&/' /etc/pam.d/postlogin
fi
if grep -q "^\s*session.*required.*pam_lastlog.so.*silent.*" /etc/pam.d/postlogin; then
# remove 'silent' option
sed -i --follow-symlinks 's/^\(session.*required.*pam_lastlog.so\).*/\1 showfailed/g' /etc/pam.d/postlogin
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83560-3
- CJIS-5.5.2
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Check for expected pam_lastlog.so entry
ansible.builtin.lineinfile:
path: /etc/pam.d/postlogin
create: false
regexp: ^\s*session.*required.*pam_lastlog.so\s\+showfailed\s*$
state: absent
check_mode: true
changed_when: false
register: result_pam_lastlog_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83560-3
- CJIS-5.5.2
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Check if system relies on authselect
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-83560-3
- CJIS-5.5.2
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Remediation where authselect tool is present
block:
- name: Check the integrity of the current authselect profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
ignore_errors: true
- name: Informative message based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd is success
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because the authselect profile is
not intact.
- It is not recommended to manually edit the PAM files when authselect is
available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Get authselect current profile
ansible.builtin.shell:
cmd: authselect current -r | awk '{ print $1 }'
register: result_authselect_profile
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Define the current authselect profile as a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is match("custom/")
- name: Define the new authselect custom profile as a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: custom/hardening
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is not match("custom/")
- name: Get authselect current features to also enable them in the custom profile
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- name: Check if any custom profile with the same name was already created in
the past
ansible.builtin.stat:
path: /etc/authselect/{{ authselect_custom_profile }}
register: result_authselect_custom_profile_present
changed_when: false
when:
- authselect_current_profile is not match("custom/")
- name: Create a custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b sssd
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Ensure the silent option is not present in the custom profile
ansible.builtin.replace:
dest: /etc/authselect/{{ authselect_custom_profile }}/postlogin
regexp: ^(session.*required.*pam_lastlog.so).*$
replace: \g<1> showfailed
when:
- result_authselect_profile is not skipped
- name: Ensure the desired configuration is present in the custom profile
ansible.builtin.lineinfile:
dest: /etc/authselect/{{ authselect_custom_profile }}/postlogin
insertbefore: ^session.*
firstmatch: true
line: session required pam_lastlog.so showfailed
when:
- result_authselect_profile is not skipped
- name: Ensure a backup of current authselect profile before selecting the custom
profile
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-pwhistory-hardening.backup
register: result_authselect_backup
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Ensure the custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }} --force
register: result_pam_authselect_select_profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Ensure the custom profile changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-pwhistory-hardening.backup
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
when:
- '"pam" in ansible_facts.packages'
- result_pam_lastlog_present.found == 0
- result_authselect_present.stat.exists
tags:
- CCE-83560-3
- CJIS-5.5.2
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Remediation where authselect tool is not present and PAM files are directly
edited
block:
- name: Ensure the silent option is not present in PAM files
ansible.builtin.replace:
dest: /etc/pam.d/postlogin
regexp: ^(session.*required.*pam_lastlog.so).*$
replace: \g<1> showfailed
- name: Ensure the desired configuration is present in PAM files
ansible.builtin.lineinfile:
dest: /etc/pam.d/postlogin
insertbefore: ^session.*
firstmatch: true
line: session required pam_lastlog.so showfailed
when:
- '"pam" in ansible_facts.packages'
- result_pam_lastlog_present.found == 0
- not result_authselect_present.stat.exists
tags:
- CCE-83560-3
- CJIS-5.5.2
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
|
Protect Physical Console Access
[ref]groupIt is impossible to fully protect a system from an
attacker with physical access, so securing the space in which the
system is located should be considered a necessary step. However,
there are some steps which, if taken, make it more difficult for an
attacker to quickly or undetectably modify a system from its
console. |
contains 2 rules |
Require Authentication for Emergency Systemd Target
[ref]ruleEmergency mode is intended as a system recovery
method, providing a single user root access to the system
during a failed boot sequence.
By default, Emergency mode is protected by requiring a password and is set
in /usr/lib/systemd/system/emergency.service . Rationale:This prevents attackers with physical access from trivially bypassing security
on the machine and gaining root access. Such accesses are further prevented
by configuring the bootloader password. Identifiers:
CCE-83592-6 References:
1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-2, AC-3, CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
service_file="/usr/lib/systemd/system/emergency.service"
sulogin="/usr/lib/systemd/systemd-sulogin-shell emergency"
if grep "^ExecStart=.*" "$service_file" ; then
sed -i "s%^ExecStart=.*%ExecStart=-$sulogin%" "$service_file"
else
echo "ExecStart=-$sulogin" >> "$service_file"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: require emergency mode password
lineinfile:
create: true
dest: /usr/lib/systemd/system/emergency.service
regexp: ^#?ExecStart=
line: ExecStart=-/usr/lib/systemd/systemd-sulogin-shell emergency
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83592-6
- NIST-800-171-3.1.1
- NIST-800-171-3.4.5
- NIST-800-53-AC-3
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- require_emergency_target_auth
- restrict_strategy
|
Require Authentication for Single User Mode
[ref]ruleSingle-user mode is intended as a system recovery
method, providing a single user root access to the system by
providing a boot option at startup. By default, no authentication
is performed if single-user mode is selected.
By default, single-user mode is protected by requiring a password and is set
in /usr/lib/systemd/system/rescue.service . Rationale:This prevents attackers with physical access from trivially bypassing security
on the machine and gaining root access. Such accesses are further prevented
by configuring the bootloader password. Identifiers:
CCE-83594-2 References:
1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-2, AC-3, CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
service_file="/usr/lib/systemd/system/rescue.service"
sulogin="/usr/lib/systemd/systemd-sulogin-shell rescue"
if grep "^ExecStart=.*" "$service_file" ; then
sed -i "s%^ExecStart=.*%ExecStart=-$sulogin%" "$service_file"
else
echo "ExecStart=-$sulogin" >> "$service_file"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: require single user mode password
lineinfile:
create: true
dest: /usr/lib/systemd/system/rescue.service
regexp: ^#?ExecStart=
line: ExecStart=-/usr/lib/systemd/systemd-sulogin-shell rescue
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83594-2
- NIST-800-171-3.1.1
- NIST-800-171-3.4.5
- NIST-800-53-AC-3
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- require_singleuser_auth
- restrict_strategy
|
Protect Accounts by Restricting Password-Based Login
[ref]groupConventionally, Unix shell accounts are accessed by
providing a username and password to a login program, which tests
these values for correctness using the /etc/passwd and
/etc/shadow files. Password-based login is vulnerable to
guessing of weak passwords, and to sniffing and man-in-the-middle
attacks against passwords entered over a network or at an insecure
console. Therefore, mechanisms for accessing accounts by entering
usernames and passwords should be restricted to those which are
operationally necessary. |
contains 7 rules |
Set Password Expiration Parameters
[ref]groupThe file /etc/login.defs controls several
password-related settings. Programs such as passwd ,
su , and
login consult /etc/login.defs to determine
behavior with regard to password aging, expiration warnings,
and length. See the man page login.defs(5) for more information.
Users should be forced to change their passwords, in order to
decrease the utility of compromised passwords. However, the need to
change passwords often should be balanced against the risk that
users will reuse or write down passwords if forced to change them
too often. Forcing password changes every 90-360 days, depending on
the environment, is recommended. Set the appropriate value as
PASS_MAX_DAYS and apply it to existing accounts with the
-M flag.
The PASS_MIN_DAYS (-m ) setting prevents password
changes for 7 days after the first change, to discourage password
cycling. If you use this setting, train users to contact an administrator
for an emergency password change in case a new password becomes
compromised. The PASS_WARN_AGE (-W ) setting gives
users 7 days of warnings at login time that their passwords are about to expire.
For example, for each existing human user USER, expiration parameters
could be adjusted to a 180 day maximum password age, 7 day minimum password
age, and 7 day warning period with the following command:
$ sudo chage -M 180 -m 7 -W 7 USER |
contains 3 rules |
Set Password Maximum Age
[ref]ruleTo specify password maximum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MAX_DAYS 60
A value of 180 days is sufficient for many environments.
The DoD requirement is 60.
The profile requirement is 60 .Rationale:Any password, no matter how complex, can eventually be cracked. Therefore, passwords
need to be changed periodically. If the operating system does not limit the lifetime
of passwords and force users to change their passwords, there is the risk that the
operating system passwords could be compromised.
Setting the password maximum age ensures users are required to
periodically change their passwords. Requiring shorter password lifetimes
increases the risk of users writing down the password in a convenient
location subject to physical compromise. Identifiers:
CCE-83606-4 References:
BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.6, CCI-000199, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(d), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.4, SRG-OS-000076-GPOS-00044 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then
var_accounts_maximum_age_login_defs='60'
grep -q ^PASS_MAX_DAYS /etc/login.defs && \
sed -i "s/PASS_MAX_DAYS.*/PASS_MAX_DAYS $var_accounts_maximum_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
echo "PASS_MAX_DAYS $var_accounts_maximum_age_login_defs" >> /etc/login.defs
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83606-4
- CJIS-5.6.2.1
- NIST-800-171-3.5.6
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.4
- accounts_maximum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_maximum_age_login_defs # promote to variable
set_fact:
var_accounts_maximum_age_login_defs: !!str 60
tags:
- always
- name: Set Password Maximum Age
lineinfile:
create: true
dest: /etc/login.defs
regexp: ^#?PASS_MAX_DAYS
line: PASS_MAX_DAYS {{ var_accounts_maximum_age_login_defs }}
when: '"shadow-utils" in ansible_facts.packages'
tags:
- CCE-83606-4
- CJIS-5.6.2.1
- NIST-800-171-3.5.6
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.4
- accounts_maximum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Minimum Age
[ref]ruleTo specify password minimum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MIN_DAYS 1
A value of 1 day is considered sufficient for many
environments. The DoD requirement is 1.
The profile requirement is 1 .Rationale:Enforcing a minimum password lifetime helps to prevent repeated password
changes to defeat the password reuse or history enforcement requirement. If
users are allowed to immediately and continually change their password,
then the password could be repeatedly changed in a short period of time to
defeat the organization's policy regarding password reuse.
Setting the minimum password age protects against users cycling back to a
favorite password after satisfying the password reuse requirement. Identifiers:
CCE-83610-6 References:
1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, CCI-000198, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(d), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000075-GPOS-00043 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then
var_accounts_minimum_age_login_defs='1'
grep -q ^PASS_MIN_DAYS /etc/login.defs && \
sed -i "s/PASS_MIN_DAYS.*/PASS_MIN_DAYS $var_accounts_minimum_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
echo "PASS_MIN_DAYS $var_accounts_minimum_age_login_defs" >> /etc/login.defs
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83610-6
- CJIS-5.6.2.1.1
- NIST-800-171-3.5.8
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- accounts_minimum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_minimum_age_login_defs # promote to variable
set_fact:
var_accounts_minimum_age_login_defs: !!str 1
tags:
- always
- name: Set Password Minimum Age
lineinfile:
create: true
dest: /etc/login.defs
regexp: ^#?PASS_MIN_DAYS
line: PASS_MIN_DAYS {{ var_accounts_minimum_age_login_defs }}
when: '"shadow-utils" in ansible_facts.packages'
tags:
- CCE-83610-6
- CJIS-5.6.2.1.1
- NIST-800-171-3.5.8
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- accounts_minimum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Warning Age
[ref]ruleTo specify how many days prior to password
expiration that a warning will be issued to users,
edit the file /etc/login.defs and add or correct
the following line:
PASS_WARN_AGE 7
The DoD requirement is 7.
The profile requirement is 7 .Rationale:Setting the password warning age enables users to
make the change at a practical time. Identifiers:
CCE-83609-8 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, 0418, 1055, 1402, A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-5(f), IA-5(1)(d), CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then
var_accounts_password_warn_age_login_defs='7'
grep -q ^PASS_WARN_AGE /etc/login.defs && \
sed -i "s/PASS_WARN_AGE.*/PASS_WARN_AGE\t$var_accounts_password_warn_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]
then
echo -e "PASS_WARN_AGE\t$var_accounts_password_warn_age_login_defs" >> /etc/login.defs
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83609-8
- NIST-800-171-3.5.8
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- accounts_password_warn_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_password_warn_age_login_defs # promote to variable
set_fact:
var_accounts_password_warn_age_login_defs: !!str 7
tags:
- always
- name: Set Password Warning Age
lineinfile:
dest: /etc/login.defs
regexp: ^PASS_WARN_AGE *[0-9]*
state: present
line: PASS_WARN_AGE {{ var_accounts_password_warn_age_login_defs }}
create: true
when: '"shadow-utils" in ansible_facts.packages'
tags:
- CCE-83609-8
- NIST-800-171-3.5.8
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- accounts_password_warn_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify Proper Storage and Existence of Password
Hashes
[ref]groupBy default, password hashes for local accounts are stored
in the second field (colon-separated) in
/etc/shadow . This file should be readable only by
processes running with root credentials, preventing users from
casually accessing others' password hashes and attempting
to crack them.
However, it remains possible to misconfigure the system
and store password hashes
in world-readable files such as /etc/passwd , or
to even store passwords themselves in plaintext on the system.
Using system-provided tools for password change/creation
should allow administrators to avoid such misconfiguration. |
contains 2 rules |
Verify All Account Password Hashes are Shadowed
[ref]ruleIf any password hashes are stored in /etc/passwd (in the second field,
instead of an x or * ), the cause of this misconfiguration should be
investigated. The account should have its password reset and the hash should be
properly stored, or the account should be deleted entirely. Rationale:The hashes for all user account passwords should be stored in
the file /etc/shadow and never in /etc/passwd ,
which is readable by all users. Identifiers:
CCE-83618-9 References:
1, 12, 15, 16, 5, 5.5.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.10, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 1410, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(h), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1 |
Prevent Login to Accounts With Empty Password
[ref]ruleIf an account is configured for password authentication
but does not have an assigned password, it may be possible to log
into the account without authentication. Remove any instances of the
nullok in
/etc/pam.d/system-auth
to prevent logins with empty passwords. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
Note that this rule is not applicable for systems running within a
container. Having user with empty password within a container is not
considered a risk, because it should not be possible to directly login into
a container anyway. Rationale:If an account has an empty password, anyone could log in and
run commands with the privileges of that account. Accounts with
empty passwords should never be used in operational environments. Identifiers:
CCE-83611-4 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2, APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10, 3.1.1, 3.1.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-5(1)(a), IA-5(c), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, FIA_UAU.1, Req-8.2.3, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEM_AUTH="/etc/pam.d/system-auth"
PASSWORD_AUTH="/etc/pam.d/password-auth"
if [ -f /usr/bin/authselect ]; then
if authselect check; then
authselect enable-feature without-nullok
authselect apply-changes
else
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because the authselect profile is not intact.
It is not recommended to manually edit the PAM files when authselect is available
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
false
fi
else
sed --follow-symlinks -i 's/\<nullok\>//g' $SYSTEM_AUTH
sed --follow-symlinks -i 's/\<nullok\>//g' $PASSWORD_AUTH
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Strategy: | configure |
---|
- name: Check if system relies on authselect
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83611-4
- CJIS-5.5.2
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- configure_strategy
- high_severity
- low_complexity
- medium_disruption
- no_empty_passwords
- no_reboot_needed
- name: Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
ignore_errors: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- result_authselect_present.stat.exists
tags:
- CCE-83611-4
- CJIS-5.5.2
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- configure_strategy
- high_severity
- low_complexity
- medium_disruption
- no_empty_passwords
- no_reboot_needed
- name: Get authselect current features
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- result_authselect_present.stat.exists
- result_authselect_check_cmd is success
tags:
- CCE-83611-4
- CJIS-5.5.2
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- configure_strategy
- high_severity
- low_complexity
- medium_disruption
- no_empty_passwords
- no_reboot_needed
- name: Ensure nullok property is absent via authselect tool
ansible.builtin.command:
cmd: authselect enable-feature without-nullok
register: result_authselect_cmd
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- result_authselect_present.stat.exists
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("without-nullok")
tags:
- CCE-83611-4
- CJIS-5.5.2
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- configure_strategy
- high_severity
- low_complexity
- medium_disruption
- no_empty_passwords
- no_reboot_needed
- name: Informative message based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd is success
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because the authselect profile is not
intact.
- It is not recommended to manually edit the PAM files when authselect is available
- In cases where the default authselect profile does not cover a specific demand,
a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83611-4
- CJIS-5.5.2
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- configure_strategy
- high_severity
- low_complexity
- medium_disruption
- no_empty_passwords
- no_reboot_needed
- name: Ensure nullok property is absent by directly editing pam files
replace:
dest: '{{ item }}'
regexp: nullok
loop:
- /etc/pam.d/system-auth
- /etc/pam.d/password-auth
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not result_authselect_present.stat.exists
tags:
- CCE-83611-4
- CJIS-5.5.2
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- configure_strategy
- high_severity
- low_complexity
- medium_disruption
- no_empty_passwords
- no_reboot_needed
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,%23%20Generated%20by%20authselect%20on%20Sat%20Oct%2027%2014%3A59%3A36%202018%0A%23%20Do%20not%20modify%20this%20file%20manually.%0A%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_env.so%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_faildelay.so%20delay%3D2000000%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_fprintd.so%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20try_first_pass%0Aauth%20%20%20%20%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet_success%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20forward_pass%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3C%201000%20quiet%0Aaccount%20%20%20%20%20%5Bdefault%3Dbad%20success%3Dok%20user_unknown%3Dignore%5D%20pam_sss.so%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_permit.so%0A%0Apassword%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_pwquality.so%20try_first_pass%20local_users_only%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20sha512%20shadow%20try_first_pass%20use_authtok%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20use_authtok%0Apassword%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_keyinit.so%20revoke%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_limits.so%0A-session%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_systemd.so%0Asession%20%20%20%20%20%5Bsuccess%3D1%20default%3Dignore%5D%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20service%20in%20crond%20quiet%20use_uid%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%0A
mode: 0644
path: /etc/pam.d/password-auth
overwrite: true
- contents:
source: data:,%23%20Generated%20by%20authselect%20on%20Sat%20Oct%2027%2014%3A59%3A36%202018%0A%23%20Do%20not%20modify%20this%20file%20manually.%0A%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_env.so%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_faildelay.so%20delay%3D2000000%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_fprintd.so%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20try_first_pass%0Aauth%20%20%20%20%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet_success%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20forward_pass%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3C%201000%20quiet%0Aaccount%20%20%20%20%20%5Bdefault%3Dbad%20success%3Dok%20user_unknown%3Dignore%5D%20pam_sss.so%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_permit.so%0A%0Apassword%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_pwquality.so%20try_first_pass%20local_users_only%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20sha512%20shadow%20try_first_pass%20use_authtok%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20use_authtok%0Apassword%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_keyinit.so%20revoke%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_limits.so%0A-session%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_systemd.so%0Asession%20%20%20%20%20%5Bsuccess%3D1%20default%3Dignore%5D%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20service%20in%20crond%20quiet%20use_uid%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%0A
mode: 0644
path: /etc/pam.d/system-auth
overwrite: true
|
Restrict Root Logins
[ref]groupDirect root logins should be allowed only for emergency use.
In normal situations, the administrator should access the system
via a unique unprivileged account, and then use su or sudo to execute
privileged commands. Discouraging administrators from accessing the
root account directly ensures an audit trail in organizations with
multiple administrators. Locking down the channels through which
root can connect directly also reduces opportunities for
password-guessing against the root account. The login program
uses the file /etc/securetty to determine which interfaces
should allow root logins.
The virtual devices /dev/console
and /dev/tty* represent the system consoles (accessible via
the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default
installation). The default securetty file also contains /dev/vc/* .
These are likely to be deprecated in most environments, but may be retained
for compatibility. Root should also be prohibited from connecting
via network protocols. Other sections of this document
include guidance describing how to prevent root from logging in via SSH. |
contains 2 rules |
Verify Only Root Has UID 0
[ref]ruleIf any account other than root has a UID of 0, this misconfiguration should
be investigated and the accounts other than root should be removed or have
their UID changed.
If the account is associated with system commands or applications the UID
should be changed to one greater than "0" but less than "1000."
Otherwise assign a UID greater than "1000" that has not already been
assigned. Rationale:An account has root authority if it has a UID of 0. Multiple accounts
with a UID of 0 afford more opportunity for potential intruders to
guess a password for a privileged account. Proper configuration of
sudo is recommended to afford multiple system administrators
access to root privileges in an accountable manner. Identifiers:
CCE-83624-7 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10, 3.1.1, 3.1.5, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-2, AC-6(5), IA-4(b), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
awk -F: '$3 == 0 && $1 != "root" { print $1 }' /etc/passwd | xargs --no-run-if-empty --max-lines=1 passwd -l
|
Ensure that System Accounts Do Not Run a Shell Upon Login
[ref]ruleSome accounts are not associated with a human user of the system, and exist to
perform some administrative function. Should an attacker be able to log into
these accounts, they should not be granted access to a shell.
The login shell for each local account is stored in the last field of each line
in /etc/passwd . System accounts are those user accounts with a user ID
less than UID_MIN, where value of UID_MIN directive is set in
/etc/login.defs configuration file. In the default configuration UID_MIN is set
to 1000, thus system accounts are those user accounts with a user ID less than
1000. The user ID is stored in the third field. If any system account
SYSACCT (other than root) has a login shell, disable it with the
command: $ sudo usermod -s /sbin/nologin SYSACCT Warning:
Do not perform the steps in this section on the root account. Doing so might
cause the system to become inaccessible. Rationale:Ensuring shells are not given to system accounts upon login makes it more
difficult for attackers to make use of system accounts. Identifiers:
CCE-83623-9 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS06.03, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, 1491, A.12.4.1, A.12.4.3, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-6, CM-6(a), CM-6(b), CM-6.1(iv), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, SRG-OS-000480-GPOS-00227 |
System Accounting with auditd
[ref]groupThe audit service provides substantial capabilities
for recording system activities. By default, the service audits about
SELinux AVC denials and certain types of security-relevant events
such as system logins, account modifications, and authentication
events performed by programs such as sudo.
Under its default configuration, auditd has modest disk space
requirements, and should not noticeably impact system performance.
NOTE: The Linux Audit daemon auditd can be configured to use
the augenrules program to read audit rules files (*.rules )
located in /etc/audit/rules.d location and compile them to create
the resulting form of the /etc/audit/audit.rules configuration file
during the daemon startup (default configuration). Alternatively, the auditd
daemon can use the auditctl utility to read audit rules from the
/etc/audit/audit.rules configuration file during daemon startup,
and load them into the kernel. The expected behavior is configured via the
appropriate ExecStartPost directive setting in the
/usr/lib/systemd/system/auditd.service configuration file.
To instruct the auditd daemon to use the augenrules program
to read audit rules (default configuration), use the following setting:
ExecStartPost=-/sbin/augenrules --load
in the /usr/lib/systemd/system/auditd.service configuration file.
In order to instruct the auditd daemon to use the auditctl
utility to read audit rules, use the following setting:
ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rules
in the /usr/lib/systemd/system/auditd.service configuration file.
Refer to [Service] section of the /usr/lib/systemd/system/auditd.service
configuration file for further details.
Government networks often have substantial auditing
requirements and auditd can be configured to meet these
requirements.
Examining some example audit records demonstrates how the Linux audit system
satisfies common requirements.
The following example from Fedora Documentation available at
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/selinux_users_and_administrators_guide/index#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages
shows the substantial amount of information captured in a
two typical "raw" audit messages, followed by a breakdown of the most important
fields. In this example the message is SELinux-related and reports an AVC
denial (and the associated system call) that occurred when the Apache HTTP
Server attempted to access the /var/www/html/file1 file (labeled with
the samba_share_t type):
type=AVC msg=audit(1226874073.147:96): avc: denied { getattr } for pid=2465 comm="httpd"
path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0
tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file
type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13
a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)
msg=audit(1226874073.147:96) - The number in parentheses is the unformatted time stamp (Epoch time)
for the event, which can be converted to standard time by using the
date command.
{ getattr } - The item in braces indicates the permission that was denied.
getattr
indicates the source process was trying to read the target file's status information.
This occurs before reading files. This action is denied due to the file being
accessed having the wrong label. Commonly seen permissions include getattr ,
read , and write .
comm="httpd" - The executable that launched the process. The full path of the executable is
found in the
exe= section of the system call (SYSCALL ) message,
which in this case, is exe="/usr/sbin/httpd" .
path="/var/www/html/file1" - The path to the object (target) the process attempted to access.
scontext="unconfined_u:system_r:httpd_t:s0" - The SELinux context of the process that attempted the denied action. In
this case, it is the SELinux context of the Apache HTTP Server, which is running
in the
httpd_t domain.
tcontext="unconfined_u:object_r:samba_share_t:s0" - The SELinux context of the object (target) the process attempted to access.
In this case, it is the SELinux context of
file1 . Note: the samba_share_t
type is not accessible to processes running in the httpd_t domain.
- From the system call (
SYSCALL ) message, two items are of interest:
success=no : indicates whether the denial (AVC) was enforced or not.
success=no indicates the system call was not successful (SELinux denied
access). success=yes indicates the system call was successful - this can
be seen for permissive domains or unconfined domains, such as initrc_t
and kernel_t .
exe="/usr/sbin/httpd" : the full path to the executable that launched
the process, which in this case, is exe="/usr/sbin/httpd" .
|
contains 33 rules |
Configure auditd Rules for Comprehensive Auditing
[ref]groupThe auditd program can perform comprehensive
monitoring of system activity. This section describes recommended
configuration settings for comprehensive auditing, but a full
description of the auditing system's capabilities is beyond the
scope of this guide. The mailing list linux-audit@redhat.com exists
to facilitate community discussion of the auditing system.
The audit subsystem supports extensive collection of events, including:
- Tracing of arbitrary system calls (identified by name or number)
on entry or exit.
- Filtering by PID, UID, call success, system call argument (with
some limitations), etc.
- Monitoring of specific files for modifications to the file's
contents or metadata.
Auditing rules at startup are controlled by the file /etc/audit/audit.rules .
Add rules to it to meet the auditing requirements for your organization.
Each line in /etc/audit/audit.rules represents a series of arguments
that can be passed to auditctl and can be individually tested
during runtime. See documentation in /usr/share/doc/audit-VERSION and
in the related man pages for more details.
If copying any example audit rulesets from /usr/share/doc/audit-VERSION ,
be sure to comment out the
lines containing arch= which are not appropriate for your system's
architecture. Then review and understand the following rules,
ensuring rules are activated as needed for the appropriate
architecture.
After reviewing all the rules, reading the following sections, and
editing as needed, the new rules can be activated as follows:
$ sudo service auditd restart |
contains 24 rules |
Record Events that Modify the System's Discretionary Access Controls
[ref]groupAt a minimum, the audit system should collect file permission
changes for all users and root. Note that the "-F arch=b32" lines should be
present even on a 64 bit system. These commands identify system calls for
auditing. Even if the system is 64 bit it can still execute 32 bit system
calls. Additionally, these rules can be configured in a number of ways while
still achieving the desired effect. An example of this is that the "-S" calls
could be split up and placed on separate lines, however, this is less efficient.
Add the following to /etc/audit/audit.rules :
-a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If your system is 64 bit then these lines should be duplicated and the
arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod |
contains 2 rules |
Record Events that Modify the System's Discretionary Access Controls - chmod
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-83830-0 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="chmod"
KEY="perm_mod"
SYSCALL_GROUPING="chmod fchmod fchmodat"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83830-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit chmod tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83830-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chmod for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83830-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chmod for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-83830-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - chown
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-83812-8 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="chown"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83812-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit chown tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83812-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chown for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83812-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chown for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-83812-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Execution Attempts to Run SELinux Privileged Commands
[ref]groupAt a minimum, the audit system should collect the execution of
SELinux privileged commands for all users and root. |
contains 6 rules |
Record Any Attempts to Run chcon
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the chcon command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-83748-4 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000463-VMM-001850 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/chcon -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83748-4
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_chcon
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/chcon
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chcon -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chcon -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chcon -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chcon -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83748-4
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_chcon
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Any Attempts to Run restorecon
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the restorecon command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-83749-2 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000392-GPOS-00172, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000463-VMM-001850 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/restorecon -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83749-2
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_restorecon
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/sbin/restorecon
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/restorecon -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/restorecon
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/restorecon -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/restorecon
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83749-2
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_restorecon
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Any Attempts to Run semanage
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the semanage command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-83750-0 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000463-VMM-001850 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/semanage -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83750-0
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_semanage
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/sbin/semanage
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/semanage -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/semanage
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/semanage -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/semanage
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83750-0
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_semanage
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Any Attempts to Run setfiles
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the setfiles command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-83736-9 References:
CCI-000169, CCI-000172, CCI-002884, AU-2(d), AU-12(c), AC-6(9), CM-6(a), SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000463-VMM-001850 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/setfiles -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83736-9
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_setfiles
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/sbin/setfiles
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/setfiles -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/setfiles
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/setfiles -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/setfiles -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/setfiles
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83736-9
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_setfiles
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Any Attempts to Run setsebool
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the setsebool command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-83751-8 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000463-VMM-001850 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/setsebool -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83751-8
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_setsebool
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/sbin/setsebool
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/setsebool -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/setsebool
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/setsebool
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83751-8
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_setsebool
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Any Attempts to Run seunshare
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the seunshare command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/sbin/seunshare -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/sbin/seunshare -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/seunshare -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83746-8
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_seunshare
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/sbin/seunshare
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/seunshare -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/seunshare -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/seunshare
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/seunshare -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/seunshare -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/seunshare
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83746-8
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_execution_seunshare
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Unauthorized Access Attempts Events to Files (unsuccessful)
[ref]groupAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. Note that the "-F arch=b32" lines should be
present even on a 64 bit system. These commands identify system calls for
auditing. Even if the system is 64 bit it can still execute 32 bit system
calls. Additionally, these rules can be configured in a number of ways while
still achieving the desired effect. An example of this is that the "-S" calls
could be split up and placed on separate lines, however, this is less efficient.
Add the following to /etc/audit/audit.rules :
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If your system is 64 bit then these lines should be duplicated and the
arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access |
contains 1 rule |
Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)
[ref]ruleAt a minimum the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
This rule checks for multiple syscalls related to unsuccessful file modification;
it was written with DISA STIG in mind. Other policies should use a
separate rule for each syscall that needs to be checked. For example:
audit_rules_unsuccessful_file_modification_open audit_rules_unsuccessful_file_modification_ftruncate audit_rules_unsuccessful_file_modification_creat
Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-83793-0 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, 0582, 0584, 05885, 0586, 0846, 0957, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.2.4, Req-10.2.1 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
# First fix the -EACCES requirement
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EACCES"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="creat open openat open_by_handle_at truncate ftruncate"
KEY="access"
SYSCALL_GROUPING="creat open openat open_by_handle_at truncate ftruncate"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Then fix the -EPERM requirement
# No need to change content of $GROUP variable - it's the same as for -EACCES case above
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F exit=-EPERM"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="creat open openat open_by_handle_at truncate ftruncate"
KEY="access"
SYSCALL_GROUPING="creat open openat open_by_handle_at truncate ftruncate"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Information on Kernel Modules Loading and Unloading
[ref]groupTo capture kernel module loading and unloading events, use following lines, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S init_module,delete_module -F key=modules
Place to add the lines depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the lines to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl utility,
add the lines to file /etc/audit/audit.rules . |
contains 1 rule |
Ensure auditd Collects Information on Kernel Module Loading and Unloading
[ref]ruleTo capture kernel module loading and unloading events, use following lines, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S init_module,finit_module,delete_module -F key=modules
The place to add the lines depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the lines to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl utility,
add the lines to file /etc/audit/audit.rules .Rationale:The addition/removal of kernel modules can be used to alter the behavior of
the kernel and potentially introduce malicious code into kernel space. It is important
to have an audit trail of modules that have been introduced into the kernel. Identifiers:
CCE-83804-5 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.2.7 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
# it's required on a 64-bit system to check also for the presence
# of 32-bit's equivalent of the corresponding rule.
# (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS=""
SYSCALL="init_module finit_module delete_module"
KEY="modules"
SYSCALL_GROUPING="init_module finit_module delete_module"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83804-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83804-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for kernel module loading for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
- delete_module
- finit_module
syscall_grouping:
- init_module
- delete_module
- finit_module
- name: Check existence of init_module, delete_module, finit_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/modules.rules
set_fact: audit_file="/etc/audit/rules.d/modules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=modules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
- delete_module
- finit_module
syscall_grouping:
- init_module
- delete_module
- finit_module
- name: Check existence of init_module, delete_module, finit_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=modules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83804-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for kernel module loading for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
- delete_module
- finit_module
syscall_grouping:
- init_module
- delete_module
- finit_module
- name: Check existence of init_module, delete_module, finit_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/modules.rules
set_fact: audit_file="/etc/audit/rules.d/modules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=modules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
- delete_module
- finit_module
syscall_grouping:
- init_module
- delete_module
- finit_module
- name: Check existence of init_module, delete_module, finit_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=modules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-83804-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Attempts to Alter Logon and Logout Events
[ref]groupThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
-w /var/run/faillock/ -p wa -k logins
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
-w /var/run/faillock/ -p wa -k logins
-w /var/log/lastlog -p wa -k logins |
contains 4 rules |
Record Attempts to Alter Logon and Logout Events
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
-w /var/run/faillock -p wa -k logins
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
-w /var/run/faillock -p wa -k logins
-w /var/log/lastlog -p wa -k logins Warning:
This rule checks for multiple syscalls related to login events;
it was written with DISA STIG in mind. Other policies should use a
separate rule for each syscall that needs to be checked. For example:
audit_rules_login_events_tallylog audit_rules_login_events_faillock audit_rules_login_events_lastlog
Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-83784-9 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.2.3 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/tallylog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/tallylog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/tallylog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/tallylog -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/tallylog" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/tallylog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/tallylog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/tallylog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/tallylog -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/run/faillock" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/faillock $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/faillock$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/faillock -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/run/faillock" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/run/faillock" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/faillock $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/faillock$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/faillock -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/lastlog" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to Alter Logon and Logout Events - faillock
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/run/faillock -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/run/faillock -p wa -k logins Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-83783-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218, SRG-OS-000473-VMM-001930, SRG-OS-000470-VMM-001900 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/run/faillock" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/faillock $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/faillock$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/faillock -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/run/faillock" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/run/faillock" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/faillock $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/faillock$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/faillock -p wa -k logins" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83783-1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k logins$
patterns: '*.rules'
register: find_faillock
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83783-1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/logins.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- find_faillock.matched is defined and find_faillock.matched == 0
tags:
- CCE-83783-1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_faillock.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_faillock.matched is defined and find_faillock.matched > 0
tags:
- CCE-83783-1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the faillock rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/run/faillock -p wa -k logins
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83783-1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the faillock rule in /etc/audit/audit.rules
lineinfile:
line: -w /var/run/faillock -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83783-1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Attempts to Alter Logon and Logout Events - lastlog
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-83785-6 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000470-GPOS-00214, SRG-OS-000473-VMM-001930, SRG-OS-000470-VMM-001900 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/lastlog" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83785-6
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k logins$
patterns: '*.rules'
register: find_lastlog
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83785-6
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/logins.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- find_lastlog.matched is defined and find_lastlog.matched == 0
tags:
- CCE-83785-6
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_lastlog.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_lastlog.matched is defined and find_lastlog.matched > 0
tags:
- CCE-83785-6
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the lastlog rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/lastlog -p wa -k logins
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83785-6
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the lastlog rule in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/lastlog -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83785-6
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Attempts to Alter Logon and Logout Events - tallylog
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-83782-3 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, CCI-000126, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218, SRG-OS-000473-VMM-001930, SRG-OS-000470-VMM-001900 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/tallylog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/tallylog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/tallylog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/tallylog -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/tallylog" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/tallylog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/tallylog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/tallylog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/tallylog -p wa -k logins" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83782-3
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k logins$
patterns: '*.rules'
register: find_tallylog
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83782-3
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/logins.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- find_tallylog.matched is defined and find_tallylog.matched == 0
tags:
- CCE-83782-3
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_tallylog.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_tallylog.matched is defined and find_tallylog.matched > 0
tags:
- CCE-83782-3
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the tallylog rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/tallylog -p wa -k logins
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83782-3
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the tallylog rule in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/tallylog -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83782-3
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Information on the Use of Privileged Commands
[ref]groupAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. |
contains 1 rule |
Ensure auditd Collects Information on the Use of Privileged Commands
[ref]ruleThe audit system should collect information about usage of privileged
commands for all users and root. To find the relevant setuid /
setgid programs, run the following command for each local partition
PART:
$ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null
If the auditd daemon is configured to use the augenrules
program to read audit rules during daemon startup (the default), add a line of
the following form to a file with suffix .rules in the directory
/etc/audit/rules.d for each setuid / setgid program on the system,
replacing the SETUID_PROG_PATH part with the full path of that setuid /
setgid program in the list:
-a always,exit -F path=SETUID_PROG_PATH -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules for each setuid / setgid program on the
system, replacing the SETUID_PROG_PATH part with the full path of that
setuid / setgid program in the list:
-a always,exit -F path=SETUID_PROG_PATH -F auid>=1000 -F auid!=unset -F key=privileged Warning:
This rule checks for multiple syscalls related to privileged commands;
it was written with DISA STIG in mind. Other policies should use a
separate rule for each syscall that needs to be checked. For example:
audit_rules_privileged_commands_su audit_rules_privileged_commands_umount audit_rules_privileged_commands_passwd
Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-83759-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO08.04, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.05, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-002234, 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.5, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.3.4.5.9, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 3.9, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, 0582, 0584, 05885, 0586, 0846, 0957, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.1, A.16.1.2, A.16.1.3, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.3, A.6.2.1, A.6.2.2, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-2, DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, DE.DP-4, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, RS.CO-2, Req-10.2.2, SRG-OS-000327-GPOS-00127, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
files_to_inspect=()
# If the audit tool is 'auditctl', then:
# * add '/etc/audit/audit.rules'to the list of files to be inspected,
# * specify '/etc/audit/audit.rules' as the output audit file, where
# missing rules should be inserted
files_to_inspect=("/etc/audit/audit.rules")
output_audit_file="/etc/audit/audit.rules"
# Obtain the list of SUID/SGID binaries on the particular system (split by newline)
# into privileged_binaries array
privileged_binaries=()
readarray -t privileged_binaries < <(find / -not \( -fstype afs -o -fstype ceph -o -fstype cifs -o -fstype smb3 -o -fstype smbfs -o -fstype sshfs -o -fstype ncpfs -o -fstype ncp -o -fstype nfs -o -fstype nfs4 -o -fstype gfs -o -fstype gfs2 -o -fstype glusterfs -o -fstype gpfs -o -fstype pvfs2 -o -fstype ocfs2 -o -fstype lustre -o -fstype davfs -o -fstype fuse.sshfs \) -type f \( -perm -4000 -o -perm -2000 \) 2> /dev/null)
# Keep list of SUID/SGID binaries that have been already handled within some previous iteration
sbinaries_to_skip=()
# For each found sbinary in privileged_binaries list
for sbinary in "${privileged_binaries[@]}"
do
# Check if this sbinary wasn't already handled in some of the previous sbinary iterations
# Return match only if whole sbinary definition matched (not in the case just prefix matched!!!)
if [[ $(sed -ne "\|${sbinary}|p" <<< "${sbinaries_to_skip[*]}") ]]
then
# If so, don't process it second time & go to process next sbinary
continue
fi
# Reset the counter of inspected files when starting to check
# presence of existing audit rule for new sbinary
count_of_inspected_files=0
# Define expected rule form for this binary
expected_rule="-a always,exit -F path=${sbinary} -F auid>=1000 -F auid!=unset -F key=privileged"
# If list of audit rules files to be inspected is empty, just add new rule and move on to next binary
if [[ ${#files_to_inspect[@]} -eq 0 ]]; then
echo "$expected_rule" >> "$output_audit_file"
continue
fi
# Replace possible slash '/' character in sbinary definition so we could use it in sed expressions below
sbinary_esc=${sbinary//$'/'/$'\/'}
# For each audit rules file from the list of files to be inspected
for afile in "${files_to_inspect[@]}"
do
# Search current audit rules file's content for match. Match criteria:
# * existing rule is for the same SUID/SGID binary we are currently processing (but
# can contain multiple -F path= elements covering multiple SUID/SGID binaries)
# * existing rule contains all arguments from expected rule form (though can contain
# them in arbitrary order)
base_search=$(sed -e '/-a always,exit/!d' -e '/-F path='"${sbinary_esc}"'[^[:graph:]]/!d' \
-e '/-F path=[^[:space:]]\+/!d' \
-e '/-F auid>='"1000"'/!d' -e '/-F auid!=\(4294967295\|unset\)/!d' \
-e '/-k \|-F key=/!d' "$afile")
# Increase the count of inspected files for this sbinary
count_of_inspected_files=$((count_of_inspected_files + 1))
# Search current audit rules file's content for presence of rule pattern for this sbinary
if [[ $base_search ]]
then
# Current audit rules file already contains rule for this binary =>
# Store the exact form of found rule for this binary for further processing
concrete_rule=$base_search
# Select all other SUID/SGID binaries possibly also present in the found rule
readarray -t handled_sbinaries < <(grep -o -e "-F path=[^[:space:]]\+" <<< "$concrete_rule")
handled_sbinaries=("${handled_sbinaries[@]//-F path=/}")
# Merge the list of such SUID/SGID binaries found in this iteration with global list ignoring duplicates
readarray -t sbinaries_to_skip < <(for i in "${sbinaries_to_skip[@]}" "${handled_sbinaries[@]}"; do echo "$i"; done | sort -du)
# if there is a -F perm flag, remove it
if grep -q '.*-F\s\+perm=[rwxa]\+.*' <<< "$concrete_rule"; then
# Separate concrete_rule into three sections using hash '#'
# sign as a delimiter around rule's permission section borders
# note that the trailing space after perm flag is captured because there would be
# two consecutive spaces after joining remaining parts of the rule together
concrete_rule="$(echo "$concrete_rule" | sed -n "s/\(.*\)\+\(-F perm=[rwax]\+\ \?\)\+/\1#\2#/p")"
# Split concrete_rule into head and tail sections using hash '#' delimiter
# The second column contains the permission section, which we don't need to extract
rule_head=$(cut -d '#' -f 1 <<< "$concrete_rule")
rule_tail=$(cut -d '#' -f 3 <<< "$concrete_rule")
# Remove permissions section from existing rule in the file
sed -i "s#${rule_head}\(.*\)${rule_tail}#${rule_head}${rule_tail}#" "$afile"
fi
# If the required audit rule for particular sbinary wasn't found yet, insert it under following conditions:
#
# * in the "auditctl" mode of operation insert particular rule each time
# (because in this mode there's only one file -- /etc/audit/audit.rules to be inspected for presence of this rule),
#
# * in the "augenrules" mode of operation insert particular rule only once and only in case we have already
# searched all of the files from /etc/audit/rules.d/*.rules location (since that audit rule can be defined
# in any of those files and if not, we want it to be inserted only once into /etc/audit/rules.d/privileged.rules file)
#
else
# Check if this sbinary wasn't already handled in some of the previous afile iterations
# Return match only if whole sbinary definition matched (not in the case just prefix matched!!!)
if [[ ! $(sed -ne "\|${sbinary}|p" <<< "${sbinaries_to_skip[*]}") ]]
then
# Current audit rules file's content doesn't contain expected rule for this
# SUID/SGID binary yet => append it
echo "$expected_rule" >> "$output_audit_file"
fi
continue
fi
done
done
files_to_inspect=()
# If the audit tool is 'augenrules', then:
# * add '/etc/audit/rules.d/*.rules' to the list of files to be inspected
# (split by newline),
# * specify /etc/audit/rules.d/privileged.rules' as the output file, where
# missing rules should be inserted
readarray -t files_to_inspect < <(find /etc/audit/rules.d -maxdepth 1 -type f -name '*.rules' -print)
output_audit_file="/etc/audit/rules.d/privileged.rules"
# Obtain the list of SUID/SGID binaries on the particular system (split by newline)
# into privileged_binaries array
privileged_binaries=()
readarray -t privileged_binaries < <(find / -not \( -fstype afs -o -fstype ceph -o -fstype cifs -o -fstype smb3 -o -fstype smbfs -o -fstype sshfs -o -fstype ncpfs -o -fstype ncp -o -fstype nfs -o -fstype nfs4 -o -fstype gfs -o -fstype gfs2 -o -fstype glusterfs -o -fstype gpfs -o -fstype pvfs2 -o -fstype ocfs2 -o -fstype lustre -o -fstype davfs -o -fstype fuse.sshfs \) -type f \( -perm -4000 -o -perm -2000 \) 2> /dev/null)
# Keep list of SUID/SGID binaries that have been already handled within some previous iteration
sbinaries_to_skip=()
# For each found sbinary in privileged_binaries list
for sbinary in "${privileged_binaries[@]}"
do
# Check if this sbinary wasn't already handled in some of the previous sbinary iterations
# Return match only if whole sbinary definition matched (not in the case just prefix matched!!!)
if [[ $(sed -ne "\|${sbinary}|p" <<< "${sbinaries_to_skip[*]}") ]]
then
# If so, don't process it second time & go to process next sbinary
continue
fi
# Reset the counter of inspected files when starting to check
# presence of existing audit rule for new sbinary
count_of_inspected_files=0
# Define expected rule form for this binary
expected_rule="-a always,exit -F path=${sbinary} -F auid>=1000 -F auid!=unset -F key=privileged"
# If list of audit rules files to be inspected is empty, just add new rule and move on to next binary
if [[ ${#files_to_inspect[@]} -eq 0 ]]; then
echo "$expected_rule" >> "$output_audit_file"
continue
fi
# Replace possible slash '/' character in sbinary definition so we could use it in sed expressions below
sbinary_esc=${sbinary//$'/'/$'\/'}
# For each audit rules file from the list of files to be inspected
for afile in "${files_to_inspect[@]}"
do
# Search current audit rules file's content for match. Match criteria:
# * existing rule is for the same SUID/SGID binary we are currently processing (but
# can contain multiple -F path= elements covering multiple SUID/SGID binaries)
# * existing rule contains all arguments from expected rule form (though can contain
# them in arbitrary order)
base_search=$(sed -e '/-a always,exit/!d' -e '/-F path='"${sbinary_esc}"'[^[:graph:]]/!d' \
-e '/-F path=[^[:space:]]\+/!d' \
-e '/-F auid>='"1000"'/!d' -e '/-F auid!=\(4294967295\|unset\)/!d' \
-e '/-k \|-F key=/!d' "$afile")
# Increase the count of inspected files for this sbinary
count_of_inspected_files=$((count_of_inspected_files + 1))
# Search current audit rules file's content for presence of rule pattern for this sbinary
if [[ $base_search ]]
then
# Current audit rules file already contains rule for this binary =>
# Store the exact form of found rule for this binary for further processing
concrete_rule=$base_search
# Select all other SUID/SGID binaries possibly also present in the found rule
readarray -t handled_sbinaries < <(grep -o -e "-F path=[^[:space:]]\+" <<< "$concrete_rule")
handled_sbinaries=("${handled_sbinaries[@]//-F path=/}")
# Merge the list of such SUID/SGID binaries found in this iteration with global list ignoring duplicates
readarray -t sbinaries_to_skip < <(for i in "${sbinaries_to_skip[@]}" "${handled_sbinaries[@]}"; do echo "$i"; done | sort -du)
# if there is a -F perm flag, remove it
if grep -q '.*-F\s\+perm=[rwxa]\+.*' <<< "$concrete_rule"; then
# Separate concrete_rule into three sections using hash '#'
# sign as a delimiter around rule's permission section borders
# note that the trailing space after perm flag is captured because there would be
# two consecutive spaces after joining remaining parts of the rule together
concrete_rule="$(echo "$concrete_rule" | sed -n "s/\(.*\)\+\(-F perm=[rwax]\+\ \?\)\+/\1#\2#/p")"
# Split concrete_rule into head and tail sections using hash '#' delimiter
# The second column contains the permission section, which we don't need to extract
rule_head=$(cut -d '#' -f 1 <<< "$concrete_rule")
rule_tail=$(cut -d '#' -f 3 <<< "$concrete_rule")
# Remove permissions section from existing rule in the file
sed -i "s#${rule_head}\(.*\)${rule_tail}#${rule_head}${rule_tail}#" "$afile"
fi
# If the required audit rule for particular sbinary wasn't found yet, insert it under following conditions:
#
# * in the "auditctl" mode of operation insert particular rule each time
# (because in this mode there's only one file -- /etc/audit/audit.rules to be inspected for presence of this rule),
#
# * in the "augenrules" mode of operation insert particular rule only once and only in case we have already
# searched all of the files from /etc/audit/rules.d/*.rules location (since that audit rule can be defined
# in any of those files and if not, we want it to be inserted only once into /etc/audit/rules.d/privileged.rules file)
#
elif [[ $count_of_inspected_files -eq "${#files_to_inspect[@]}" ]]
then
# Check if this sbinary wasn't already handled in some of the previous afile iterations
# Return match only if whole sbinary definition matched (not in the case just prefix matched!!!)
if [[ ! $(sed -ne "\|${sbinary}|p" <<< "${sbinaries_to_skip[*]}") ]]
then
# Current audit rules file's content doesn't contain expected rule for this
# SUID/SGID binary yet => append it
echo "$expected_rule" >> "$output_audit_file"
fi
continue
fi
done
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83759-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- audit_rules_privileged_commands
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search for privileged commands
shell: |
set -o pipefail
find / -not \( -fstype afs -o -fstype ceph -o -fstype cifs -o -fstype smb3 -o -fstype smbfs -o -fstype sshfs -o -fstype ncpfs -o -fstype ncp -o -fstype nfs -o -fstype nfs4 -o -fstype gfs -o -fstype gfs2 -o -fstype glusterfs -o -fstype gpfs -o -fstype pvfs2 -o -fstype ocfs2 -o -fstype lustre -o -fstype davfs -o -fstype fuse.sshfs \) -type f \( -perm -4000 -o -perm -2000 \) 2> /dev/null
args:
warn: false
executable: /bin/bash
check_mode: false
register: find_result
changed_when: false
failed_when: false
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83759-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- audit_rules_privileged_commands
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for audit rule entries
find:
paths: /etc/audit/rules.d
recurse: false
contains: ^.*path={{ item }} .*$
patterns: '*.rules'
with_items:
- '{{ find_result.stdout_lines }}'
register: files_result
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83759-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- audit_rules_privileged_commands
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Overwrites the rule in rules.d
lineinfile:
path: '{{ item.1.path }}'
line: -a always,exit -F path={{ item.0.item }} -F auid>=1000 -F auid!=unset -F
key=privileged
create: false
regexp: ^.*path={{ item.0.item }} .*$
with_subelements:
- '{{ files_result.results }}'
- files
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83759-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- audit_rules_privileged_commands
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Adds the rule in rules.d
lineinfile:
path: /etc/audit/rules.d/privileged.rules
line: -a always,exit -F path={{ item.item }} -F auid>=1000 -F auid!=unset -F key=privileged
create: true
with_items:
- '{{ files_result.results }}'
when:
- '"audit" in ansible_facts.packages'
- files_result.results is defined and item.matched == 0
tags:
- CCE-83759-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- audit_rules_privileged_commands
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces the rule in audit.rules
lineinfile:
path: /etc/audit/audit.rules
line: -a always,exit -F path={{ item.item }} -F auid>=1000 -F auid!=unset -F key=privileged
create: true
regexp: ^.*path={{ item.item }} .*$
with_items:
- '{{ files_result.results }}'
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83759-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- audit_rules_privileged_commands
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Records Events that Modify Date and Time Information
[ref]groupArbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time. All changes to the system
time should be audited. |
contains 5 rules |
Record attempts to alter time through adjtimex
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be
used for better reporting capability through ausearch and aureport. Multiple
system calls can be defined on the same line to save space if desired, but is
not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-83840-9 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
# Create expected audit group and audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday stime"
SYSCALL_GROUPING="adjtimex settimeofday stime"
elif [ ${ARCH} = "b64" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday"
SYSCALL_GROUPING="adjtimex settimeofday"
fi
OTHER_FILTERS=""
AUID_FILTERS=""
KEY="audit_time_rules"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83840-9
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83840-9
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for adjtimex for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of adjtimex in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of adjtimex in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83840-9
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for adjtimex for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- name: Check existence of adjtimex in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of adjtimex in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-83840-9
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -a%20always%2Cexit%20-F%20arch%3Db64%20-S%20adjtimex%20-k%20audit_time_rules%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20adjtimex%20-k%20audit_time_rules%0A }}
mode: 0600
path: /etc/audit/rules.d/75-syscall-adjtimex.rules
overwrite: true
|
Record Attempts to Alter Time Through clock_settime
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport.
Multiple system calls can be defined on the same line to save space if
desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-83837-5 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F a0=0x0"
AUID_FILTERS=""
SYSCALL="clock_settime"
KEY="time-change"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83837-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83837-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for clock_settime for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/time-change.rules
set_fact: audit_file="/etc/audit/rules.d/time-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83837-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for clock_settime for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/time-change.rules
set_fact: audit_file="/etc/audit/rules.d/time-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-83837-5
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -a%20always%2Cexit%20-F%20arch%3Db64%20-S%20clock_settime%20-F%20a0%3D0x0%20-k%20time-change%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20clock_settime%20-F%20a0%3D0x0%20-k%20time-change%0A }}
mode: 0600
path: /etc/audit/rules.d/75-syscall-clock-settime.rules
overwrite: true
|
Record attempts to alter time through settimeofday
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be
used for better reporting capability through ausearch and aureport. Multiple
system calls can be defined on the same line to save space if desired, but is
not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-83836-7 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
# Create expected audit group and audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday stime"
SYSCALL_GROUPING="adjtimex settimeofday stime"
elif [ ${ARCH} = "b64" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday"
SYSCALL_GROUPING="adjtimex settimeofday"
fi
OTHER_FILTERS=""
AUID_FILTERS=""
KEY="audit_time_rules"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83836-7
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_settimeofday
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83836-7
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_settimeofday
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for settimeofday for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- settimeofday
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of settimeofday in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- settimeofday
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of settimeofday in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83836-7
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_settimeofday
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for settimeofday for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- settimeofday
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of settimeofday in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- settimeofday
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of settimeofday in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-83836-7
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_settimeofday
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -a%20always%2Cexit%20-F%20arch%3Db64%20-S%20settimeofday%20-k%20audit_time_rules%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20settimeofday%20-k%20audit_time_rules%0A }}
mode: 0600
path: /etc/audit/rules.d/75-syscall-settimeofday.rules
overwrite: true
|
Record Attempts to Alter Time Through stime
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit
lookup table, the corresponding "-F arch=b64" form of this rule is not expected
to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule
form itself is sufficient for both 32 bit and 64 bit systems). If the
auditd daemon is configured to use the auditctl utility to
read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit
lookup table, the corresponding "-F arch=b64" form of this rule is not expected
to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule
form itself is sufficient for both 32 bit and 64 bit systems). The -k option
allows for the specification of a key in string form that can be used for
better reporting capability through ausearch and aureport. Multiple system
calls can be defined on the same line to save space if desired, but is not
required. See an example of multiple combined system calls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-83835-9 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
# Create expected audit group and audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday stime"
SYSCALL_GROUPING="adjtimex settimeofday stime"
elif [ ${ARCH} = "b64" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday"
SYSCALL_GROUPING="adjtimex settimeofday"
fi
OTHER_FILTERS=""
AUID_FILTERS=""
KEY="audit_time_rules"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83835-9
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_stime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for stime syscall for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- stime
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of stime in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- stime
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of stime in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83835-9
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_stime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -a%20always%2Cexit%20-F%20arch%3Db64%20-S%20stime%20-k%20audit_time_rules%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20stime%20-k%20audit_time_rules%0A }}
mode: 0600
path: /etc/audit/rules.d/75-syscall-stime.rules
overwrite: true
|
Record Attempts to Alter the localtime File
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the default),
add the following line to a file with suffix .rules in the directory
/etc/audit/rules.d :
-w /etc/localtime -p wa -k audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/localtime -p wa -k audit_time_rules
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport and
should always be used.Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-83839-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/localtime" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/localtime $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/localtime$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/localtime -p wa -k audit_time_rules" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_time_rules.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/localtime" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_time_rules.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_time_rules.rules"
# If the audit_time_rules.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/localtime" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/localtime $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/localtime$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/localtime -p wa -k audit_time_rules" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83839-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/localtime already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83839-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_time_rules
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83839-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_time_rules.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83839-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83839-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/localtime in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/localtime -p wa -k audit_time_rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83839-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/localtime already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83839-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/localtime in /etc/audit/audit.rules
lineinfile:
line: -w /etc/localtime -p wa -k audit_time_rules
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-83839-1
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -w%20/etc/localtime%20-p%20wa%20-k%20audit_time_rules%0A }}
mode: 0600
path: /etc/audit/rules.d/75-etclocaltime-wa-audit_time_rules.rules
overwrite: true
|
Record Events that Modify the System's Network Environment
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification Rationale:The network environment should not be modified by anything other
than administrator action. Any change to network parameters should be
audited. Identifiers:
CCE-83706-2 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.5.5 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS=""
SYSCALL="sethostname setdomainname"
KEY="audit_rules_networkconfig_modification"
SYSCALL_GROUPING="sethostname setdomainname"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
# Then perform the remediations for the watch rules
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/issue" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/issue" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/issue" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/issue.net" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue.net $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue.net$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/issue.net" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/issue.net" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue.net $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue.net$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/hosts" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/hosts $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/hosts$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/hosts -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/hosts" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/hosts" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/hosts $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/hosts$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/hosts -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/sysconfig/network" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sysconfig/network $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sysconfig/network$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sysconfig/network" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/sysconfig/network" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sysconfig/network $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sysconfig/network$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remediate audit rules for network configuration for x86
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
set_fact: audit_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remediate audit rules for network configuration for x86_64
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
set_fact: audit_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue in /etc/audit/audit.rules
lineinfile:
line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue.net already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue.net in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue.net already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue.net in /etc/audit/audit.rules
lineinfile:
line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/hosts already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/hosts in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/hosts already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/hosts in /etc/audit/audit.rules
lineinfile:
line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/sysconfig/network in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/sysconfig/network in /etc/audit/audit.rules
lineinfile:
line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-83706-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Attempts to Alter Process and Session Initiation Information
[ref]ruleThe audit system already collects process information for all
users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-83713-8 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, 0582, 0584, 05885, 0586, 0846, 0957, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/run/utmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/utmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/run/utmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/run/utmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/utmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/btmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/wtmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/run/utmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/run/utmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/run/utmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/run/utmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/run/utmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/run/utmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/btmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/btmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/btmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/btmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/wtmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/wtmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/wtmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/wtmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-83713-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %0A-w%20/var/run/utmp%20-p%20wa%20-k%20session%0A-w%20/var/log/btmp%20-p%20wa%20-k%20session%0A-w%20/var/log/wtmp%20-p%20wa%20-k%20session%0A }}
mode: 0600
path: /etc/audit/rules.d/75-audit-session-events.rules
overwrite: true
|
Ensure auditd Collects System Administrator Actions
[ref]ruleAt a minimum, the audit system should collect administrator actions
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the default),
add the following line to a file with suffix .rules in the directory
/etc/audit/rules.d :
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions Rationale:The actions taken by system administrators should be audited to keep a record
of what was executed on the system, as well as, for accountability purposes. Identifiers:
CCE-83729-4 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(7)(b), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.2, Req-10.2.5.b, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000462-VMM-001840, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/actions.rules"
# If the actions.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers.d/" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/actions.rules"
# If the actions.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83729-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for audit rule entries for sysadmin actions
find:
paths: /etc/audit/rules.d
recurse: false
contains: ^.*/etc/sudoers.*$
patterns: '*.rules'
register: find_audit_sysadmin_actions
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83729-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/actions.rules as the recipient for the rule
set_fact:
all_sysadmin_actions_files:
- /etc/audit/rules.d/actions.rules
when:
- '"audit" in ansible_facts.packages'
- find_audit_sysadmin_actions.matched is defined and find_audit_sysadmin_actions.matched
== 0
tags:
- CCE-83729-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_sysadmin_actions_files:
- '{{ find_audit_sysadmin_actions.files | map(attribute=''path'') | list | first
}}'
when:
- '"audit" in ansible_facts.packages'
- find_audit_sysadmin_actions.matched is defined and find_audit_sysadmin_actions.matched
> 0
tags:
- CCE-83729-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers rule in rules.d
lineinfile:
path: '{{ all_sysadmin_actions_files[0] }}'
line: -w /etc/sudoers -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83729-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers.d rule in rules.d
lineinfile:
path: '{{ all_sysadmin_actions_files[0] }}'
line: -w /etc/sudoers.d/ -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83729-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers in audit.rules
lineinfile:
path: /etc/audit/audit.rules
line: -w /etc/sudoers -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83729-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers.d in audit.rules
lineinfile:
path: /etc/audit/audit.rules
line: -w /etc/sudoers.d/ -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83729-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(7)(b)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ -w%20/etc/sudoers.d/%20-p%20wa%20-k%20actions%0A-w%20/etc/sudoers%20-p%20wa%20-k%20actions%0A }}
mode: 0600
path: /etc/audit/rules.d/75-audit-sysadmin-actions.rules
overwrite: true
|
Record Events that Modify User/Group Information
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification Warning:
This rule checks for multiple syscalls related to account changes;
it was written with DISA STIG in mind. Other policies should use a
separate rule for each syscall that needs to be checked. For example:
audit_rules_usergroup_modification_group audit_rules_usergroup_modification_gshadow audit_rules_usergroup_modification_passwd
Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-83715-3 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000172, CCI-001403, CCI-002130, 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000239-GPOS-00089, SRG-OS-000241-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000476-GPOS-00221 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/group" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/group $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/group$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/group -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/group" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/group" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/group $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/group$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/group -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/passwd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/passwd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/passwd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/passwd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/passwd" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/passwd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/passwd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/passwd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/passwd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/gshadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/gshadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/gshadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/gshadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/gshadow" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/gshadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/gshadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/gshadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/gshadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/shadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/shadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/shadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/shadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/shadow" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/shadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/shadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/shadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/shadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/security/opasswd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/security/opasswd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/security/opasswd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/security/opasswd" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/security/opasswd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/security/opasswd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/security/opasswd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure auditd Data Retention
[ref]groupThe audit system writes data to /var/log/audit/audit.log . By default,
auditd rotates 5 logs by size (6MB), retaining a maximum of 30MB of
data in total, and refuses to write entries when the disk is too
full. This minimizes the risk of audit data filling its partition
and impacting other services. This also minimizes the risk of the audit
daemon temporarily disabling the system if it cannot write audit log (which
it can be configured to do).
For a busy
system or a system which is thoroughly auditing system activity, the default settings
for data retention may be
insufficient. The log file size needed will depend heavily on what types
of events are being audited. First configure auditing to log all the events of
interest. Then monitor the log size manually for awhile to determine what file
size will allow you to keep the required data for the correct time period.
Using a dedicated partition for /var/log/audit prevents the
auditd logs from disrupting system functionality if they fill, and,
more importantly, prevents other activity in /var from filling the
partition and stopping the audit trail. (The audit logs are size-limited and
therefore unlikely to grow without bound unless configured to do so.) Some
machines may have requirements that no actions occur which cannot be audited.
If this is the case, then auditd can be configured to halt the machine
if it runs out of space. Note: Since older logs are rotated,
configuring auditd this way does not prevent older logs from being
rotated away before they can be viewed.
If your system is configured to halt when logging cannot be performed, make
sure this can never happen under normal circumstances! Ensure that
/var/log/audit is on its own partition, and that this partition is
larger than the maximum amount of data auditd will retain
normally. |
contains 6 rules |
Configure auditd flush priority
[ref]ruleThe auditd service can be configured to
synchronously write audit event data to disk. Add or correct the following
line in /etc/audit/auditd.conf to ensure that audit event data is
fully synchronized with the log files on the disk:
flush = incremental_async Rationale:Audit data should be synchronously written to disk to ensure
log integrity. These parameters assure that all audit event data is fully
synchronized with the log files on the disk. Identifiers:
CCE-83685-8 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, CCI-001576, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-6 R2.2.3, CIP-004-6 R3.3, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AU-11, CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
var_auditd_flush='incremental_async'
AUDITCONFIG=/etc/audit/auditd.conf
# if flush is present, flush param edited to var_auditd_flush
# else flush param is defined by var_auditd_flush
#
# the freq param is only used for values 'incremental' and 'incremental_async' and will be
# commented out if flush != incremental or flush != incremental_async
#
# if flush == incremental or flush == incremental_async && freq param is not defined, it
# will be defined as the package-default value of 20
grep -q ^flush $AUDITCONFIG && \
sed -i 's/^flush.*/flush = '"$var_auditd_flush"'/g' $AUDITCONFIG
if ! [ $? -eq 0 ]; then
echo "flush = $var_auditd_flush" >> $AUDITCONFIG
fi
if ! [ "$var_auditd_flush" == "incremental" ] && ! [ "$var_auditd_flush" == "incremental_async" ]; then
sed -i 's/^freq/##freq/g' $AUDITCONFIG
elif [ "$var_auditd_flush" == "incremental" ] || [ "$var_auditd_flush" == "incremental_async" ]; then
grep -q freq $AUDITCONFIG && \
sed -i 's/^#\+freq/freq/g' $AUDITCONFIG
if ! [ $? -eq 0 ]; then
echo "freq = 20" >> $AUDITCONFIG
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83685-8
- NIST-800-171-3.3.1
- NIST-800-53-AU-11
- NIST-800-53-CM-6(a)
- auditd_data_retention_flush
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_flush # promote to variable
set_fact:
var_auditd_flush: !!str incremental_async
tags:
- always
- name: Configure auditd Flush Priority
lineinfile:
dest: /etc/audit/auditd.conf
regexp: ^\s*flush\s*=\s*.*$
line: flush = {{ var_auditd_flush }}
state: present
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83685-8
- NIST-800-171-3.3.1
- NIST-800-53-AU-11
- NIST-800-53-CM-6(a)
- auditd_data_retention_flush
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
mode: 0640
path: /etc/audit/auditd.conf
overwrite: true
|
Set number of records to cause an explicit flush to audit logs
[ref]ruleTo configure Audit daemon to issue an explicit flush to disk command
after writing 50 records, set freq to 50
in /etc/audit/auditd.conf . Rationale:If option freq isn't set to 50 , the flush to disk
may happen after higher number of records, increasing the danger
of audit loss. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
if [ -e "/etc/audit/auditd.conf" ] ; then
LC_ALL=C sed -i "/^\s*freq\s*=\s*/Id" "/etc/audit/auditd.conf"
else
touch "/etc/audit/auditd.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/audit/auditd.conf"
cp "/etc/audit/auditd.conf" "/etc/audit/auditd.conf.bak"
# Insert at the end of the file
printf '%s\n' "freq = 50" >> "/etc/audit/auditd.conf"
# Clean up after ourselves.
rm "/etc/audit/auditd.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83704-7
- NIST-800-53-CM-6
- auditd_freq
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set number of records to cause an explicit flush to audit logs
block:
- name: Check for duplicate values
lineinfile:
path: /etc/audit/auditd.conf
create: false
regexp: (?i)^\s*freq\s*=\s*
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/audit/auditd.conf
lineinfile:
path: /etc/audit/auditd.conf
create: false
regexp: (?i)^\s*freq\s*=\s*
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/audit/auditd.conf
lineinfile:
path: /etc/audit/auditd.conf
create: true
regexp: (?i)^\s*freq\s*=\s*
line: freq = 50
state: present
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83704-7
- NIST-800-53-CM-6
- auditd_freq
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
mode: 0640
path: /etc/audit/auditd.conf
overwrite: true
|
Include Local Events in Audit Logs
[ref]ruleTo configure Audit daemon to include local events in Audit logs, set
local_events to yes in /etc/audit/auditd.conf .
This is the default setting. Rationale:If option local_events isn't set to yes only events from
network will be aggregated. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
if [ -e "/etc/audit/auditd.conf" ] ; then
LC_ALL=C sed -i "/^\s*local_events\s*=\s*/Id" "/etc/audit/auditd.conf"
else
touch "/etc/audit/auditd.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/audit/auditd.conf"
cp "/etc/audit/auditd.conf" "/etc/audit/auditd.conf.bak"
# Insert at the end of the file
printf '%s\n' "local_events = yes" >> "/etc/audit/auditd.conf"
# Clean up after ourselves.
rm "/etc/audit/auditd.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83682-5
- NIST-800-53-CM-6
- auditd_local_events
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Include Local Events in Audit Logs
block:
- name: Check for duplicate values
lineinfile:
path: /etc/audit/auditd.conf
create: false
regexp: (?i)^\s*local_events\s*=\s*
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/audit/auditd.conf
lineinfile:
path: /etc/audit/auditd.conf
create: false
regexp: (?i)^\s*local_events\s*=\s*
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/audit/auditd.conf
lineinfile:
path: /etc/audit/auditd.conf
create: true
regexp: (?i)^\s*local_events\s*=\s*
line: local_events = yes
state: present
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83682-5
- NIST-800-53-CM-6
- auditd_local_events
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
mode: 0640
path: /etc/audit/auditd.conf
overwrite: true
|
Resolve information before writing to audit logs
[ref]ruleTo configure Audit daemon to resolve all uid, gid, syscall,
architecture, and socket address information before writing the
events to disk, set log_format to ENRICHED
in /etc/audit/auditd.conf . Rationale:If option log_format isn't set to ENRICHED , the
audit records will be stored in a format exactly as the kernel sends them. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
if [ -e "/etc/audit/auditd.conf" ] ; then
LC_ALL=C sed -i "/^\s*log_format\s*=\s*/Id" "/etc/audit/auditd.conf"
else
touch "/etc/audit/auditd.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/audit/auditd.conf"
cp "/etc/audit/auditd.conf" "/etc/audit/auditd.conf.bak"
# Insert at the end of the file
printf '%s\n' "log_format = ENRICHED" >> "/etc/audit/auditd.conf"
# Clean up after ourselves.
rm "/etc/audit/auditd.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83696-5
- NIST-800-53-AU-3
- NIST-800-53-CM-6
- auditd_log_format
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Resolve information before writing to audit logs
block:
- name: Check for duplicate values
lineinfile:
path: /etc/audit/auditd.conf
create: false
regexp: (?i)^\s*log_format\s*=\s*
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/audit/auditd.conf
lineinfile:
path: /etc/audit/auditd.conf
create: false
regexp: (?i)^\s*log_format\s*=\s*
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/audit/auditd.conf
lineinfile:
path: /etc/audit/auditd.conf
create: true
regexp: (?i)^\s*log_format\s*=\s*
line: log_format = ENRICHED
state: present
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83696-5
- NIST-800-53-AU-3
- NIST-800-53-CM-6
- auditd_log_format
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
mode: 0640
path: /etc/audit/auditd.conf
overwrite: true
|
Set hostname as computer node name in audit logs
[ref]ruleTo configure Audit daemon to use value returned by gethostname
syscall as computer node name in the audit events,
set name_format to hostname
in /etc/audit/auditd.conf . Rationale:If option name_format is left at its default value of
none , audit events from different computers may be hard
to distinguish. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
if [ -e "/etc/audit/auditd.conf" ] ; then
LC_ALL=C sed -i "/^\s*name_format\s*=\s*/Id" "/etc/audit/auditd.conf"
else
touch "/etc/audit/auditd.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/audit/auditd.conf"
cp "/etc/audit/auditd.conf" "/etc/audit/auditd.conf.bak"
# Insert at the end of the file
printf '%s\n' "name_format = hostname" >> "/etc/audit/auditd.conf"
# Clean up after ourselves.
rm "/etc/audit/auditd.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83686-6
- NIST-800-53-AU-3
- NIST-800-53-CM-6
- auditd_name_format
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set hostname as computer node name in audit logs
block:
- name: Check for duplicate values
lineinfile:
path: /etc/audit/auditd.conf
create: false
regexp: (?i)^\s*name_format\s*=\s*
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/audit/auditd.conf
lineinfile:
path: /etc/audit/auditd.conf
create: false
regexp: (?i)^\s*name_format\s*=\s*
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/audit/auditd.conf
lineinfile:
path: /etc/audit/auditd.conf
create: true
regexp: (?i)^\s*name_format\s*=\s*
line: name_format = hostname
state: present
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83686-6
- NIST-800-53-AU-3
- NIST-800-53-CM-6
- auditd_name_format
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
mode: 0640
path: /etc/audit/auditd.conf
overwrite: true
|
Write Audit Logs to the Disk
[ref]ruleTo configure Audit daemon to write Audit logs to the disk, set
write_logs to yes in /etc/audit/auditd.conf .
This is the default setting. Rationale:If write_logs isn't set to yes , the Audit logs will
not be written to the disk. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
if [ -e "/etc/audit/auditd.conf" ] ; then
LC_ALL=C sed -i "/^\s*write_logs\s*=\s*/Id" "/etc/audit/auditd.conf"
else
touch "/etc/audit/auditd.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/audit/auditd.conf"
cp "/etc/audit/auditd.conf" "/etc/audit/auditd.conf.bak"
# Insert at the end of the file
printf '%s\n' "write_logs = yes" >> "/etc/audit/auditd.conf"
# Clean up after ourselves.
rm "/etc/audit/auditd.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83705-4
- NIST-800-53-CM-6
- auditd_write_logs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Write Audit Logs to the Disk
block:
- name: Check for duplicate values
lineinfile:
path: /etc/audit/auditd.conf
create: false
regexp: (?i)^\s*write_logs\s*=\s*
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/audit/auditd.conf
lineinfile:
path: /etc/audit/auditd.conf
create: false
regexp: (?i)^\s*write_logs\s*=\s*
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/audit/auditd.conf
lineinfile:
path: /etc/audit/auditd.conf
create: true
regexp: (?i)^\s*write_logs\s*=\s*
line: write_logs = yes
state: present
when: '"audit" in ansible_facts.packages'
tags:
- CCE-83705-4
- NIST-800-53-CM-6
- auditd_write_logs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
mode: 0640
path: /etc/audit/auditd.conf
overwrite: true
|
System Accounting with auditd
[ref]groupThe auditd program can perform comprehensive
monitoring of system activity. This section makes use of recommended
configuration settings for specific policies or use cases.
The rules in this section make use of rules defined in /usr/share/doc/audit-VERSION/rules . |
contains 2 rules |
Configure auditing of unsuccessful file accesses
[ref]ruleEnsure that unsuccessful attempts to access a file are audited.
The following rules configure audit as described above:
## Unsuccessful file access (any other opens) This has to go last.
-a always,exit -F arch=b32 -S open,openat,openat2,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
-a always,exit -F arch=b64 -S open,openat,openat2,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
-a always,exit -F arch=b32 -S open,openat,openat2,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
-a always,exit -F arch=b64 -S open,openat,openat2,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
Load new Audit rules into kernel by running:
augenrules --load
Note: This rule utilizes a file provided by Audit package to comply with OSPP 4.2.1. You may reuse this rule in different profiles. If you decide to do so, it is recommended that you inspect contents of the file closely and make sure that they are alligned with your needs.Rationale:Unsuccessful attempts to access a file might be signs of malicious activity happening within the system. Auditing of such activities helps in their monitoring and investigation. Identifiers:
CCE-83672-6 References:
0582, 0584, 05885, 0586, 0846, 0957, AU-2(a), FAU_GEN.1.1.c, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000475-GPOS-00220, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000461-GPOS-00205 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
cat << 'EOF' > /etc/audit/rules.d/30-ospp-v42-3-access-failed.rules
## Unsuccessful file access (any other opens) This has to go last.
-a always,exit -F arch=b32 -S open,openat,openat2,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
-a always,exit -F arch=b64 -S open,openat,openat2,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
-a always,exit -F arch=b32 -S open,openat,openat2,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
-a always,exit -F arch=b64 -S open,openat,openat2,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
EOF
chmod o-rwx /etc/audit/rules.d/30-ospp-v42-3-access-failed.rules
augenrules --load
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Put contents into /etc/audit/rules.d/30-ospp-v42-3-access-failed.rules according
to policy
copy:
dest: /etc/audit/rules.d/30-ospp-v42-3-access-failed.rules
content: |
## Unsuccessful file access (any other opens) This has to go last.
-a always,exit -F arch=b32 -S open,openat,openat2,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
-a always,exit -F arch=b64 -S open,openat,openat2,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
-a always,exit -F arch=b32 -S open,openat,openat2,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
-a always,exit -F arch=b64 -S open,openat,openat2,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-access
force: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83672-6
- NIST-800-53-AU-2(a)
- audit_access_failed
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remove any permissions from other group
file:
path: /etc/audit/rules.d/30-ospp-v42-3-access-failed.rules
mode: o-rwx
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83672-6
- NIST-800-53-AU-2(a)
- audit_access_failed
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,%23%23%20Unsuccessful%20file%20access%20%28any%20other%20opens%29%20This%20has%20to%20go%20last.%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EACCES%20-F%20auid%26gt%3B%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccessful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EACCES%20-F%20auid%26gt%3B%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccessful-access%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EPERM%20-F%20auid%26gt%3B%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccessful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EPERM%20-F%20auid%26gt%3B%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccessful-access
mode: 0600
path: /etc/audit/rules.d/30-ospp-v42-3-access-failed.rules
overwrite: true
|
Configure auditing of successful file accesses
[ref]ruleEnsure that successful attempts to access a file are audited.
The following rules configure audit as described above:
## Successful file access (any other opens) This has to go last.
## These next two are likely to result in a whole lot of events
-a always,exit -F arch=b32 -S open,openat,openat2,open_by_handle_at -F success=1 -F auid>=1000 -F auid!=unset -F key=successful-access
-a always,exit -F arch=b64 -S open,openat,openat2,open_by_handle_at -F success=1 -F auid>=1000 -F auid!=unset -F key=successful-access
The Audit package provides pre-configured rules in /usr/share/audit/sample-rules . The above content can be found in /usr/share/audit/sample-rules/30-ospp-v42-3-access-success.rules .
To deploy this configuration, it is recommended to copy it over to the /etc/audit/rules.d/ directory:
cp /usr/share/audit/sample-rules/30-ospp-v42-3-access-success.rules /etc/audit/rules.d/
Load new Audit rules into kernel by running:
augenrules --load
Note: This rule utilizes a file provided by Audit package to comply with OSPP 4.2.1. You may reuse this rule in different profiles. If you decide to do so, it is recommended that you inspect contents of the file closely and make sure that they are alligned with your needs.Rationale:Auditing of successful attempts to access a file helps in investigation of activities performed on the system. Identifiers:
CCE-83653-6 References:
0582, 0584, 05885, 0586, 0846, 0957, AU-2(a), FAU_GEN.1.1.c, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000475-GPOS-00220, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000461-GPOS-00205 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
cat << 'EOF' > /etc/audit/rules.d/30-ospp-v42-3-access-success.rules
## Successful file access (any other opens) This has to go last.
## These next two are likely to result in a whole lot of events
-a always,exit -F arch=b32 -S open,openat,openat2,open_by_handle_at -F success=1 -F auid>=1000 -F auid!=unset -F key=successful-access
-a always,exit -F arch=b64 -S open,openat,openat2,open_by_handle_at -F success=1 -F auid>=1000 -F auid!=unset -F key=successful-access
EOF
chmod o-rwx /etc/audit/rules.d/30-ospp-v42-3-access-success.rules
augenrules --load
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Put contents into /etc/audit/rules.d/30-ospp-v42-3-access-success.rules according
to policy
copy:
dest: /etc/audit/rules.d/30-ospp-v42-3-access-success.rules
content: |
## Successful file access (any other opens) This has to go last.
## These next two are likely to result in a whole lot of events
-a always,exit -F arch=b32 -S open,openat,openat2,open_by_handle_at -F success=1 -F auid>=1000 -F auid!=unset -F key=successful-access
-a always,exit -F arch=b64 -S open,openat,openat2,open_by_handle_at -F success=1 -F auid>=1000 -F auid!=unset -F key=successful-access
force: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83653-6
- NIST-800-53-AU-2(a)
- audit_access_success
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remove any permissions from other group
file:
path: /etc/audit/rules.d/30-ospp-v42-3-access-success.rules
mode: o-rwx
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83653-6
- NIST-800-53-AU-2(a)
- audit_access_success
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,%23%23%20Successful%20file%20access%20%28any%20other%20opens%29%20This%20has%20to%20go%20last.%0A%23%23%20These%20next%20two%20are%20likely%20to%20result%20in%20a%20whole%20lot%20of%20events%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Copenat%2Copen_by_handle_at%20-F%20success%3D1%20-F%20auid%26gt%3B%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dsuccessful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Copenat%2Copen_by_handle_at%20-F%20success%3D1%20-F%20auid%26gt%3B%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dsuccessful-access
mode: 0600
path: /etc/audit/rules.d/30-ospp-v42-3-access-success.rules
overwrite: true
|
Enable auditd Service
[ref]ruleThe auditd service is an essential userspace component of
the Linux Auditing System, as it is responsible for writing audit records to
disk.
The auditd service can be enabled with the following command:
$ sudo systemctl enable auditd.service Rationale:Without establishing what type of events occurred, it would be difficult
to establish, correlate, and investigate the events leading up to an outage or attack.
Ensuring the auditd service is active ensures audit records
generated by the kernel are appropriately recorded.
Additionally, a properly configured audit subsystem ensures that actions of
individual system users can be uniquely traced to those users so they
can be held accountable for their actions. Identifiers:
CCE-90829-3 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.3.2, 3.3.6, CCI-000126, CCI-000130, CCI-000131, CCI-000132, CCI-000133, CCI-000134, CCI-000135, CCI-000154, CCI-000158, CCI-000366, CCI-001464, CCI-001487, CCI-001814, CCI-001876, CCI-002884, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, CIP-004-6 R3.3, CIP-007-3 R6.5, AC-2(g), AU-3, AU-10, AU-2(d), AU-12(c), AU-14(1), AC-6(9), CM-6(a), SI-4(23), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1, Req-10.1, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000480-GPOS-00227, SRG-OS-000062-GPOS-00031, SRG-OS-000037-VMM-000150, SRG-OS-000063-VMM-000310, SRG-OS-000038-VMM-000160, SRG-OS-000039-VMM-000170, SRG-OS-000040-VMM-000180, SRG-OS-000041-VMM-000190 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q audit; }; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'auditd.service'
"$SYSTEMCTL_EXEC" start 'auditd.service'
"$SYSTEMCTL_EXEC" enable 'auditd.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-90829-3
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-171-3.3.2
- NIST-800-171-3.3.6
- NIST-800-53-AC-2(g)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-10
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-14(1)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-4(23)
- PCI-DSS-Req-10.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_auditd_enabled
- name: Enable service auditd
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service auditd
service:
name: auditd
enabled: 'yes'
state: started
masked: 'no'
when:
- '"audit" in ansible_facts.packages'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"audit" in ansible_facts.packages'
tags:
- CCE-90829-3
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-171-3.3.2
- NIST-800-171-3.3.6
- NIST-800-53-AC-2(g)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-10
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-14(1)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-4(23)
- PCI-DSS-Req-10.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_auditd_enabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include enable_auditd
class enable_auditd {
service {'auditd':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: auditd.service
enabled: true
Remediation script: (show)
[customizations.services]
enabled = ["auditd"]
|
Configure Syslog
[ref]groupThe syslog service has been the default Unix logging mechanism for
many years. It has a number of downsides, including inconsistent log format,
lack of authentication for received messages, and lack of authentication,
encryption, or reliable transport for messages sent over a network. However,
due to its long history, syslog is a de facto standard which is supported by
almost all Unix applications.
In Red Hat Enterprise Linux 9, rsyslog has replaced ksyslogd as the
syslog daemon of choice, and it includes some additional security features
such as reliable, connection-oriented (i.e. TCP) transmission of logs, the
option to log to database formats, and the encryption of log data en route to
a central logging server.
This section discusses how to configure rsyslog for
best effect, and how to use tools provided with the system to maintain and
monitor logs. |
contains 10 rules |
Ensure Proper Configuration of Log Files
[ref]groupThe file /etc/rsyslog.conf controls where log message are written.
These are controlled by lines called rules, which consist of a
selector and an action.
These rules are often customized depending on the role of the system, the
requirements of the environment, and whatever may enable
the administrator to most effectively make use of log data.
The default rules in Red Hat Enterprise Linux 9 are:
*.info;mail.none;authpriv.none;cron.none /var/log/messages
authpriv.* /var/log/secure
mail.* -/var/log/maillog
cron.* /var/log/cron
*.emerg *
uucp,news.crit /var/log/spooler
local7.* /var/log/boot.log
See the man page rsyslog.conf(5) for more information.
Note that the rsyslog daemon can be configured to use a timestamp format that
some log processing programs may not understand. If this occurs,
edit the file /etc/rsyslog.conf and add or edit the following line:
$ ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat |
contains 4 rules |
Ensure cron Is Logging To Rsyslog
[ref]ruleCron logging must be implemented to spot intrusions or trace
cron job status. If cron is not logging to rsyslog , it
can be implemented by adding the following to the RULES section of
/etc/rsyslog.conf :
cron.* /var/log/cron Rationale:Cron logging can be used to trace the successful or unsuccessful execution
of cron jobs. It can also be used to spot intrusions into the use of the cron
facility by unauthorized and malicious users. Identifiers:
CCE-83994-4 References:
1, 14, 15, 16, 3, 5, 6, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, CCI-000366, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, 0988, 1405, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.15.2.1, A.15.2.2, CM-6(a), ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! grep -s "^\s*cron\.\*\s*/var/log/cron$" /etc/rsyslog.conf /etc/rsyslog.d/*.conf; then
mkdir -p /etc/rsyslog.d
echo "cron.* /var/log/cron" >> /etc/rsyslog.d/cron.conf
fi
systemctl restart rsyslog.service
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure Log Files Are Owned By Appropriate Group
[ref]ruleThe group-owner of all log files written by
rsyslog should be root .
These log files are determined by the second part of each Rule line in
/etc/rsyslog.conf and typically all appear in /var/log .
For each log file LOGFILE referenced in /etc/rsyslog.conf ,
run the following command to inspect the file's group owner:
$ ls -l LOGFILE
If the owner is not root , run the following command to
correct this:
$ sudo chgrp root LOGFILE Rationale:The log files generated by rsyslog contain valuable information regarding system
configuration, user authentication, and other such information. Log files should be
protected from unauthorized access. Identifiers:
CCE-83834-2 References:
BP28(R46), BP28(R5), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001314, 4.3.3.7.3, SR 2.1, SR 5.2, 0988, 1405, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-10.5.1, Req-10.5.2 |
Ensure Log Files Are Owned By Appropriate User
[ref]ruleThe owner of all log files written by
rsyslog should be root .
These log files are determined by the second part of each Rule line in
/etc/rsyslog.conf and typically all appear in /var/log .
For each log file LOGFILE referenced in /etc/rsyslog.conf ,
run the following command to inspect the file's owner:
$ ls -l LOGFILE
If the owner is not root , run the following command to
correct this:
$ sudo chown root LOGFILE Rationale:The log files generated by rsyslog contain valuable information regarding system
configuration, user authentication, and other such information. Log files should be
protected from unauthorized access. Identifiers:
CCE-83946-4 References:
BP28(R46), BP28(R5), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001314, 4.3.3.7.3, SR 2.1, SR 5.2, 0988, 1405, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-10.5.1, Req-10.5.2 |
Ensure System Log Files Have Correct Permissions
[ref]ruleThe file permissions for all log files written by rsyslog should
be set to 600, or more restrictive. These log files are determined by the
second part of each Rule line in /etc/rsyslog.conf and typically
all appear in /var/log . For each log file LOGFILE
referenced in /etc/rsyslog.conf , run the following command to
inspect the file's permissions:
$ ls -l LOGFILE
If the permissions are not 600 or more restrictive, run the following
command to correct this:
$ sudo chmod 0600 LOGFILE "Rationale:Log files can contain valuable information regarding system
configuration. If the system log files are not protected unauthorized
users could change the logged data, eliminating their forensic value. Identifiers:
CCE-83689-0 References:
BP28(R36), CCI-001314, 0988, 1405, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), Req-10.5.1, Req-10.5.2 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# List of log file paths to be inspected for correct permissions
# * Primarily inspect log file paths listed in /etc/rsyslog.conf
RSYSLOG_ETC_CONFIG="/etc/rsyslog.conf"
# * And also the log file paths listed after rsyslog's $IncludeConfig directive
# (store the result into array for the case there's shell glob used as value of IncludeConfig)
readarray -t RSYSLOG_INCLUDE_CONFIG < <(grep -e "\$IncludeConfig[[:space:]]\+[^[:space:];]\+" /etc/rsyslog.conf | cut -d ' ' -f 2)
readarray -t RSYSLOG_INCLUDE < <(awk '/)/{f=0} /include\(/{f=1} f{nf=gensub("^(include\\(|\\s*)file=\"(\\S+)\".*","\\2",1); if($0!=nf){print nf}}' /etc/rsyslog.conf)
# Declare an array to hold the final list of different log file paths
declare -a LOG_FILE_PATHS
declare -a RSYSLOG_CONFIGS
RSYSLOG_CONFIGS+=("${RSYSLOG_ETC_CONFIG}" "${RSYSLOG_INCLUDE_CONFIG[@]}" "${RSYSLOG_INCLUDE[@]}")
# Browse each file selected above as containing paths of log files
# ('/etc/rsyslog.conf' and '/etc/rsyslog.d/*.conf' in the default configuration)
for LOG_FILE in "${RSYSLOG_CONFIGS[@]}"
do
# From each of these files extract just particular log file path(s), thus:
# * Ignore lines starting with space (' '), comment ('#"), or variable syntax ('$') characters,
# * Ignore empty lines,
# * Strip quotes and closing brackets from paths.
# * Ignore paths that match /dev|/etc.*\.conf, as those are paths, but likely not log files
# * From the remaining valid rows select only fields constituting a log file path
# Text file column is understood to represent a log file path if and only if all of the following are met:
# * it contains at least one slash '/' character,
# * it is preceded by space
# * it doesn't contain space (' '), colon (':'), and semicolon (';') characters
# Search log file for path(s) only in case it exists!
if [[ -f "${LOG_FILE}" ]]
then
NORMALIZED_CONFIG_FILE_LINES=$(sed -e "/^[#|$]/d" "${LOG_FILE}")
LINES_WITH_PATHS=$(grep '[^/]*\s\+\S*/\S\+$' <<< "${NORMALIZED_CONFIG_FILE_LINES}")
FILTERED_PATHS=$(sed -e 's/[^\/]*[[:space:]]*\([^:;[:space:]]*\)/\1/g' <<< "${LINES_WITH_PATHS}")
CLEANED_PATHS=$(sed -e "s/[\"')]//g; /\\/etc.*\.conf/d; /\\/dev\\//d" <<< "${FILTERED_PATHS}")
MATCHED_ITEMS=$(sed -e "/^$/d" <<< "${CLEANED_PATHS}")
# Since above sed command might return more than one item (delimited by newline), split the particular
# matches entries into new array specific for this log file
readarray -t ARRAY_FOR_LOG_FILE <<< "$MATCHED_ITEMS"
# Concatenate the two arrays - previous content of $LOG_FILE_PATHS array with
# items from newly created array for this log file
LOG_FILE_PATHS+=("${ARRAY_FOR_LOG_FILE[@]}")
# Delete the temporary array
unset ARRAY_FOR_LOG_FILE
fi
done
DESIRED_PERM_MOD=600
# Correct the form o
for LOG_FILE_PATH in "${LOG_FILE_PATHS[@]}"
do
# Sanity check - if particular $LOG_FILE_PATH is empty string, skip it from further processing
if [ -z "$LOG_FILE_PATH" ]
then
continue
fi
# Also for each log file check if its permissions differ from 600. If so, correct them
if [ -f "$LOG_FILE_PATH" ] && [ "$(/usr/bin/stat -c %a "$LOG_FILE_PATH")" -ne $DESIRED_PERM_MOD ]
then
/bin/chmod $DESIRED_PERM_MOD "$LOG_FILE_PATH"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure rsyslogd to Accept Remote Messages If Acting as a Log Server
[ref]groupBy default, rsyslog does not listen over the network
for log messages. If needed, modules can be enabled to allow
the rsyslog daemon to receive messages from other systems and for the system
thus to act as a log server.
If the system is not a log server, then lines concerning these modules
should remain commented out.
|
contains 1 rule |
Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
[ref]ruleThe rsyslog daemon should not accept remote messages
unless the system acts as a log server.
To ensure that it is not listening on the network, ensure the following lines are
not found in /etc/rsyslog.conf :
$ModLoad imtcp
$InputTCPServerRun port
$ModLoad imudp
$UDPServerRun port
$ModLoad imrelp
$InputRELPServerRun port Rationale:Any process which receives messages from the network incurs some risk
of receiving malicious messages. This risk can be eliminated for
rsyslog by configuring it not to listen on the network. Identifiers:
CCE-83995-1 References:
1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, MEA02.01, CCI-000318, CCI-000366, CCI-000368, CCI-001812, CCI-001813, CCI-001814, 4.2.3.4, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.8, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, 0988, 1405, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.IP-1, PR.PT-1, PR.PT-4, SRG-OS-000480-GPOS-00227 |
Rsyslog Logs Sent To Remote Host
[ref]groupIf system logs are to be useful in detecting malicious
activities, it is necessary to send logs to a remote server. An
intruder who has compromised the root account on a system may
delete the log entries which indicate that the system was attacked
before they are seen by an administrator.
However, it is recommended that logs be stored on the local
host in addition to being sent to the loghost, especially if
rsyslog has been configured to use the UDP protocol to send
messages over a network. UDP does not guarantee reliable delivery,
and moderately busy sites will lose log messages occasionally,
especially in periods of high traffic which may be the result of an
attack. In addition, remote rsyslog messages are not
authenticated in any way by default, so it is easy for an attacker to
introduce spurious messages to the central log server. Also, some
problems cause loss of network connectivity, which will prevent the
sending of messages to the central server. For all of these reasons, it is
better to store log messages both centrally and on each host, so
that they can be correlated if necessary. |
contains 3 rules |
Ensure Logs Sent To Remote Host
[ref]ruleTo configure rsyslog to send logs to a remote log server,
open /etc/rsyslog.conf and read and understand the last section of the file,
which describes the multiple directives necessary to activate remote
logging.
Along with these other directives, the system can be configured
to forward its logs to a particular log server by
adding or correcting one of the following lines,
substituting logcollector appropriately.
The choice of protocol depends on the environment of the system;
although TCP and RELP provide more reliable message delivery,
they may not be supported in all environments.
To use UDP for log message delivery:
*.* @logcollector
To use TCP for log message delivery:
*.* @@logcollector
To use RELP for log message delivery:
*.* :omrelp:logcollector
There must be a resolvable DNS CNAME or Alias record set to "logcollector" for logs to be sent correctly to the centralized logging utility.Rationale:A log server (loghost) receives syslog messages from one or more
systems. This data can be used as an additional log source in the event a
system is compromised and its local logs are suspect. Forwarding log messages
to a remote loghost also provides system administrators with a centralized
place to view the status of multiple hosts within the enterprise. Identifiers:
CCE-83990-2 References:
BP28(R7), NT28(R43), NT12(R5), 1, 13, 14, 15, 16, 2, 3, 5, 6, APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.04, DSS05.07, MEA02.01, CCI-000366, CCI-001348, CCI-000136, CCI-001851, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(B), 164.308(a)(5)(ii)(C), 164.308(a)(6)(ii), 164.308(a)(8), 164.310(d)(2)(iii), 164.312(b), 164.314(a)(2)(i)(C), 164.314(a)(2)(iii), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 7.1, SR 7.2, 0988, 1405, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.17.2.1, CIP-003-8 R5.2, CIP-004-6 R3.3, CM-6(a), AU-4(1), AU-9(2), PR.DS-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000479-GPOS-00224, SRG-OS-000480-GPOS-00227, SRG-OS-000342-GPOS-00133, SRG-OS-000032-VMM-000130 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
rsyslog_remote_loghost_address='logcollector'
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/rsyslog.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^\*\.\*")
# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "@@$rsyslog_remote_loghost_address"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^\*\.\*\\>" "/etc/rsyslog.conf"; then
"${sed_command[@]}" "s/^\*\.\*\\>.*/$formatted_output/gi" "/etc/rsyslog.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83990-2"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/rsyslog.conf" >> "/etc/rsyslog.conf"
printf '%s\n' "$formatted_output" >> "/etc/rsyslog.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value rsyslog_remote_loghost_address # promote to variable
set_fact:
rsyslog_remote_loghost_address: !!str logcollector
tags:
- always
- name: Set rsyslog remote loghost
lineinfile:
dest: /etc/rsyslog.conf
regexp: ^\*\.\*
line: '*.* @@{{ rsyslog_remote_loghost_address }}'
create: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83990-2
- NIST-800-53-AU-4(1)
- NIST-800-53-AU-9(2)
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- rsyslog_remote_loghost
|
Configure TLS for rsyslog remote logging
[ref]ruleConfigure rsyslog to use Transport Layer
Security (TLS) support for logging to remote server
for the Forwarding Output Module in /etc/rsyslog.conf
using action. You can use the following command:
echo 'action(type="omfwd" protocol="tcp" Target="<remote system>" port="6514"
StreamDriver="gtls" StreamDriverMode="1" StreamDriverAuthMode="x509/name" streamdriver.CheckExtendedKeyPurpose="on")' >> /etc/rsyslog.conf
Replace the <remote system> in the above command with an IP address or a host name of the remote logging server.Rationale:For protection of data being logged, the connection to the
remote logging server needs to be authenticated and encrypted. Identifiers:
CCE-83991-0 References:
BP28(R43), 0988, 1405, AU-9(3), CM-6(a), FCS_TLSC_EXT.1, FTP_ITC_EXT.1.1, FIA_X509_EXT.1.1, FMT_SMF_EXT.1.1, SRG-OS-000480-GPOS-00227, SRG-OS-000120-GPOS-00061 |
Configure CA certificate for rsyslog remote logging
[ref]ruleConfigure CA certificate for rsyslog logging
to remote server using Transport Layer Security (TLS)
using correct path for the DefaultNetstreamDriverCAFile
global option in /etc/rsyslog.conf , for example with the following command:
echo 'global(DefaultNetstreamDriverCAFile="/etc/pki/tls/cert.pem")' >> /etc/rsyslog.conf
Replace the /etc/pki/tls/cert.pem in the above command with the path to the file with CA certificate generated for the purpose of remote logging.Rationale:The CA certificate needs to be set or rsyslog.service
fails to start with
error: ca certificate is not set, cannot continue |
Ensure rsyslog is Installed
[ref]ruleRsyslog is installed by default. The rsyslog package can be installed with the following command: $ sudo dnf install rsyslog Rationale:The rsyslog package provides the rsyslog daemon, which provides
system logging services. Identifiers:
CCE-84063-7 References:
BP28(R5), NT28(R46), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, CCI-001311, CCI-001312, CCI-000366, 164.312(a)(2)(ii), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), PR.PT-1, FTP_ITC_EXT.1.1, SRG-OS-000479-GPOS-00224, SRG-OS-000051-GPOS-00024, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "rsyslog" ; then
dnf install -y "rsyslog"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure rsyslog is installed
package:
name: rsyslog
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84063-7
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_rsyslog_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_rsyslog
class install_rsyslog {
package { 'rsyslog':
ensure => 'installed',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
package --add=rsyslog
Remediation script: (show)
[[packages]]
name = "rsyslog"
version = "*"
|
Enable rsyslog Service
[ref]ruleThe rsyslog service provides syslog-style logging by default on Red Hat Enterprise Linux 9.
The rsyslog service can be enabled with the following command:
$ sudo systemctl enable rsyslog.service Rationale:The rsyslog service must be running in order to provide
logging services, which are essential to system administration. Identifiers:
CCE-83989-4 References:
BP28(R5), NT28(R46), 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO13.01, BAI03.05, BAI04.04, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, CCI-001311, CCI-001312, CCI-001557, CCI-001851, CCI-000366, 164.312(a)(2)(ii), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, A.17.2.1, CM-6(a), AU-4(1), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.DS-4, PR.PT-1, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'rsyslog.service'
"$SYSTEMCTL_EXEC" start 'rsyslog.service'
"$SYSTEMCTL_EXEC" enable 'rsyslog.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Enable service rsyslog
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service rsyslog
service:
name: rsyslog
enabled: 'yes'
state: started
masked: 'no'
when:
- '"rsyslog" in ansible_facts.packages'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83989-4
- NIST-800-53-AU-4(1)
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_rsyslog_enabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include enable_rsyslog
class enable_rsyslog {
service {'rsyslog':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
[customizations.services]
enabled = ["rsyslog"]
|
Network Configuration and Firewalls
[ref]groupMost systems must be connected to a network of some
sort, and this brings with it the substantial risk of network
attack. This section discusses the security impact of decisions
about networking which must be made when configuring a system.
This section also discusses firewalls, network access
controls, and other network security frameworks, which allow
system-level rules to be written that can limit an attackers' ability
to connect to your system. These rules can specify that network
traffic should be allowed or denied from certain IP addresses,
hosts, and networks. The rules can also specify which of the
system's network services are available to particular hosts or
networks. |
contains 7 rules |
firewalld
[ref]groupThe dynamic firewall daemon firewalld provides a
dynamically managed firewall with support for network “zones” to assign
a level of trust to a network and its associated connections and interfaces.
It has support for IPv4 and IPv6 firewall settings. It supports Ethernet
bridges and has a separation of runtime and permanent configuration options.
It also has an interface for services or applications to add firewall rules
directly.
A graphical configuration tool, firewall-config , is used to configure
firewalld , which in turn uses iptables tool to communicate
with Netfilter in the kernel which implements packet filtering.
The firewall service provided by firewalld is dynamic rather than
static because changes to the configuration can be made at anytime and are
immediately implemented. There is no need to save or apply the changes. No
unintended disruption of existing network connections occurs as no part of
the firewall has to be reloaded. |
contains 4 rules |
Inspect and Activate Default firewalld Rules
[ref]groupFirewalls can be used to separate networks into different zones
based on the level of trust the user has decided to place on the devices and
traffic within that network. NetworkManager informs firewalld to which
zone an interface belongs. An interface's assigned zone can be changed by
NetworkManager or via the firewall-config tool.
The zone settings in /etc/firewalld/ are a range of preset settings
which can be quickly applied to a network interface. These are the zones
provided by firewalld sorted according to the default trust level of the
zones from untrusted to trusted:
drop
Any incoming network packets are dropped, there is no
reply. Only outgoing network connections are possible. block
Any incoming network connections are rejected with an
icmp-host-prohibited message for IPv4 and icmp6-adm-prohibited
for IPv6. Only network connections initiated from within the system are
possible. public
For use in public areas. You do not trust the other
computers on the network to not harm your computer. Only selected incoming
connections are accepted. external
For use on external networks with masquerading enabled
especially for routers. You do not trust the other computers on the network to
not harm your computer. Only selected incoming connections are accepted. dmz
For computers in your demilitarized zone that are
publicly-accessible with limited access to your internal network. Only selected
incoming connections are accepted. work
For use in work areas. You mostly trust the other computers
on networks to not harm your computer. Only selected incoming connections are
accepted. home
For use in home areas. You mostly trust the other computers
on networks to not harm your computer. Only selected incoming connections are
accepted. internal
For use on internal networks. You mostly trust the
other computers on the networks to not harm your computer. Only selected
incoming connections are accepted. trusted
All network connections are accepted.
It is possible to designate one of these zones to be the default zone. When
interface connections are added to NetworkManager , they are assigned
to the default zone. On installation, the default zone in firewalld is set to
be the public zone.
To find out all the settings of a zone, for example the public zone,
enter the following command as root:
# firewall-cmd --zone=public --list-all
Example output of this command might look like the following:
# firewall-cmd --zone=public --list-all
public
interfaces:
services: mdns dhcpv6-client ssh
ports:
forward-ports:
icmp-blocks: source-quench
To view the network zones currently active, enter the following command as root:
# firewall-cmd --get-service
The following listing displays the result of this command
on common Red Hat Enterprise Linux 9 system:
# firewall-cmd --get-service
amanda-client bacula bacula-client dhcp dhcpv6 dhcpv6-client dns ftp
high-availability http https imaps ipp ipp-client ipsec kerberos kpasswd
ldap ldaps libvirt libvirt-tls mdns mountd ms-wbt mysql nfs ntp openvpn
pmcd pmproxy pmwebapi pmwebapis pop3s postgresql proxy-dhcp radius rpc-bind
samba samba-client smtp ssh telnet tftp tftp-client transmission-client
vnc-server wbem-https
Finally to view the network zones that will be active after the next firewalld
service reload, enter the following command as root:
# firewall-cmd --get-service --permanent |
contains 2 rules |
Install firewalld Package
[ref]ruleThe firewalld package can be installed with the following command:
$ sudo dnf install firewalld Rationale:The firewalld package should be installed to provide access control methods. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "firewalld" ; then
dnf install -y "firewalld"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure firewalld is installed
package:
name: firewalld
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84021-5
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_firewalld_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_firewalld
class install_firewalld {
package { 'firewalld':
ensure => 'installed',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
package --add=firewalld
Remediation script: (show)
[[packages]]
name = "firewalld"
version = "*"
|
Verify firewalld Enabled
[ref]rule
The firewalld service can be enabled with the following command:
$ sudo systemctl enable firewalld.service Rationale:Access control methods provide the ability to enhance system security posture
by restricting services and known good IP addresses and address ranges. This
prevents connections from unknown hosts and protocols. Identifiers:
CCE-90833-5 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.3, 3.4.7, CCI-000366, CCI-000382, CCI-002314, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CIP-003-8 R4, CIP-003-8 R5, CIP-004-6 R3, AC-4, CM-7(b), CA-3(5), SC-7(21), CM-6(a), PR.IP-1, FMT_MOF_EXT.1, SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00231, SRG-OS-000480-GPOS-00232 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'firewalld.service'
"$SYSTEMCTL_EXEC" start 'firewalld.service'
"$SYSTEMCTL_EXEC" enable 'firewalld.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Enable service firewalld
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service firewalld
service:
name: firewalld
enabled: 'yes'
state: started
masked: 'no'
when:
- '"firewalld" in ansible_facts.packages'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90833-5
- NIST-800-171-3.1.3
- NIST-800-171-3.4.7
- NIST-800-53-AC-4
- NIST-800-53-CA-3(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(21)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_firewalld_enabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include enable_firewalld
class enable_firewalld {
service {'firewalld':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
[customizations.services]
enabled = ["firewalld"]
|
Strengthen the Default Ruleset
[ref]groupThe default rules can be strengthened. The system
scripts that activate the firewall rules expect them to be defined
in configuration files under the /etc/firewalld/services
and /etc/firewalld/zones directories.
The following recommendations describe how to strengthen the
default ruleset configuration file. An alternative to editing this
configuration file is to create a shell script that makes calls to
the firewall-cmd program to load in rules under the /etc/firewalld/services
and /etc/firewalld/zones directories.
Instructions apply to both unless otherwise noted. Language and address
conventions for regular firewalld rules are used throughout this section. Warning:
The program firewall-config
allows additional services to penetrate the default firewall rules
and automatically adjusts the firewalld ruleset(s). |
contains 2 rules |
Configure the Firewalld Ports
[ref]ruleConfigure the firewalld ports to allow approved
services to have access to the system. To configure firewalld
to open ports, run the following command:
$ sudo firewall-cmd --permanent --add-port=port_number/tcp
or
$ sudo firewall-cmd --permanent --add-port=service_name
Run the command list above for each of the ports listed below:
To configure firewalld to allow access, run the following command(s):
firewall-cmd --permanent --add-service=ssh Rationale:In order to prevent unauthorized connection of devices, unauthorized
transfer of information, or unauthorized tunneling (i.e., embedding of data
types within data types), organizations must disable or restrict unused or
unnecessary physical and logical ports/protocols on information systems.
Operating systems are capable of providing a wide variety of functions and
services. Some of the functions and services provided by default may not be
necessary to support essential organizational operations.
Additionally, it is sometimes convenient to provide multiple services from
a single component (e.g., VPN and IPS); however, doing so increases risk
over limiting the services provided by any one component.
To support the requirements and principles of least functionality, the
operating system must support the organizational requirements, providing
only essential capabilities and limiting the use of ports, protocols,
and/or services to only those required, authorized, and approved to conduct
official business or to address authorized quality of life issues. Identifiers:
CCE-86041-1 References:
11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000382, CCI-002314, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, 1416, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-4, CM-7(b), CA-3(5), SC-7(21), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000096-VMM-000490, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "firewalld" ; then
dnf install -y "firewalld"
fi
firewalld_sshd_zone='public'
# This assumes that firewalld_sshd_zone is one of the pre-defined zones
if [ ! -f "/etc/firewalld/zones/${firewalld_sshd_zone}.xml" ]; then
cp "/usr/lib/firewalld/zones/${firewalld_sshd_zone}.xml" "/etc/firewalld/zones/${firewalld_sshd_zone}.xml"
fi
if ! grep -q 'service name="ssh"' "/etc/firewalld/zones/${firewalld_sshd_zone}.xml"; then
sed -i '/<\/description>/a \
<service name="ssh"/>' "/etc/firewalld/zones/${firewalld_sshd_zone}.xml"
fi
# Check if any eth interface is bounded to the zone with SSH service enabled
nic_bound=false
readarray -t eth_interface_list < <(ip link show up | cut -d ' ' -f2 | cut -d ':' -s -f1 | grep -E '^(en|eth)')
for interface in "${eth_interface_list[@]}"; do
if grep -qi "ZONE=$firewalld_sshd_zone" "/etc/NetworkManager/system-connections/${interface}.nmconnection"; then
nic_bound=true
break;
fi
done
if [ $nic_bound = false ];then
# Add first NIC to SSH enabled zone
interface="${eth_interface_list[0]}"
if ! firewall-cmd --state -q; then
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/NetworkManager/system-connections/${interface}.nmconnection"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^zone=")
# shellcheck disable=SC2059
printf -v formatted_output "%s=%s" "$stripped_key" "$firewalld_sshd_zone"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^zone=\\>" "/etc/NetworkManager/system-connections/${interface}.nmconnection"; then
"${sed_command[@]}" "s/^zone=\\>.*/$formatted_output/gi" "/etc/NetworkManager/system-connections/${interface}.nmconnection"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-86041-1"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/NetworkManager/system-connections/${interface}.nmconnection" >> "/etc/NetworkManager/system-connections/${interface}.nmconnection"
printf '%s\n' "$formatted_output" >> "/etc/NetworkManager/system-connections/${interface}.nmconnection"
fi
else
# If firewalld service is running, we need to do this step with firewall-cmd
# Otherwise firewalld will communicate with NetworkManage and will revert assigned zone
# of NetworkManager managed interfaces upon reload
firewall-cmd --permanent --zone="$firewalld_sshd_zone" --add-interface="${eth_interface_list[0]}"
firewall-cmd --reload
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Default firewalld Zone for Incoming Packets
[ref]ruleTo set the default zone to drop for
the built-in default zone which processes incoming IPv4 and IPv6 packets,
modify the following line in
/etc/firewalld/firewalld.conf to be:
DefaultZone=drop Warning:
To prevent denying any access to the system, automatic remediation
of this control is not available. Remediation must be automated as
a component of machine provisioning, or followed manually as outlined
above. Rationale:In firewalld the default zone is applied only after all
the applicable rules in the table are examined for a match. Setting the
default zone to drop implements proper design for a firewall, i.e.
any packets which are not explicitly permitted should not be
accepted. Identifiers:
CCE-84023-1 References:
11, 14, 3, 9, 5.10.1, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.3, 3.4.7, 3.13.6, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, 1416, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CA-3(5), CM-7(b), SC-7(23), CM-6(a), PR.IP-1, PR.PT-3, FMT_MOF_EXT.1, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000 |
Wireless Networking
[ref]groupWireless networking, such as 802.11
(WiFi) and Bluetooth, can present a security risk to sensitive or
classified systems and networks. Wireless networking hardware is
much more likely to be included in laptop or portable systems than
in desktops or servers.
Removal of hardware provides the greatest assurance that the wireless
capability remains disabled. Acquisition policies often include provisions to
prevent the purchase of equipment that will be used in sensitive spaces and
includes wireless capabilities. If it is impractical to remove the wireless
hardware, and policy permits the device to enter sensitive spaces as long
as wireless is disabled, efforts should instead focus on disabling wireless capability
via software. |
contains 1 rule |
Disable Wireless Through Software Configuration
[ref]groupIf it is impossible to remove the wireless hardware
from the device in question, disable as much of it as possible
through software. The following methods can disable software
support for wireless networking, but note that these methods do not
prevent malicious software or careless users from re-activating the
devices. |
contains 1 rule |
Deactivate Wireless Network Interfaces
[ref]ruleDeactivating wireless network interfaces should prevent
normal usage of the wireless capability.
Configure the system to disable all wireless network interfaces with the
following command:
$ sudo nmcli radio wifi off Rationale:The use of wireless networking can introduce many different attack vectors into
the organization's network. Common attack vectors such as malicious association
and ad hoc networks will allow an attacker to spoof a wireless access point
(AP), allowing validated systems to connect to the malicious AP and enabling the
attacker to monitor and record network traffic. These malicious APs can also
serve to create a man-in-the-middle attack or be used to create a denial of
service to valid network resources. Identifiers:
CCE-84066-0 References:
11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.1.16, CCI-000085, CCI-002418, CCI-002421, CCI-001444, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, 1315, 1319, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-18(a), AC-18(3), CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000299-GPOS-00117, SRG-OS-000300-GPOS-00118, SRG-OS-000424-GPOS-00188, SRG-OS-000481-GPOS-000481 Remediation Shell script: (show) Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Deactivate Wireless Network Interfaces
command: nmcli radio wifi off
tags:
- CCE-84066-0
- NIST-800-171-3.1.16
- NIST-800-53-AC-18(3)
- NIST-800-53-AC-18(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- wireless_disable_interfaces
|
Prevent non-Privileged Users from Modifying Network Interfaces using nmcli
[ref]ruleBy default, non-privileged users are given permissions to modify networking
interfaces and configurations using the nmcli command. Non-privileged
users should not be making configuration changes to network configurations. To
ensure that non-privileged users do not have permissions to make changes to the
network configuration using nmcli , create the following configuration in
/etc/polkit-1/localauthority/20-org.d/10-nm-harden-access.pkla :
[Disable General User Access to NetworkManager]
Identity=default
Action=org.freedesktop.NetworkManager.*
ResultAny=no
ResultInactive=no
ResultActive=auth_admin
Rationale:Allowing non-privileged users to make changes to network settings can allow
untrusted access, prevent system availability, and/or can lead to a compromise or
attack. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
printf "[Disable General User Access to NetworkManager]\nIdentity=default\nAction=org.freedesktop.NetworkManager.*\nResultAny=no\nResultInactive=no\nResultActive=auth_admin\n" > /etc/polkit-1/localauthority/20-org.d/10-nm-harden-access.pkla
|
Ensure System is Not Acting as a Network Sniffer
[ref]ruleThe system should not be acting as a network sniffer, which can
capture all traffic on the network to which it is connected. Run the following
to determine if any interface is running in promiscuous mode:
$ ip link | grep PROMISC
Promiscuous mode of an interface can be disabled with the following command:
$ sudo ip link set dev device_name multicast off promisc off Rationale:Network interfaces in promiscuous mode allow for the capture of all network traffic
visible to the system. If unauthorized individuals can access these applications, it
may allow them to collect information such as logon IDs, passwords, and key exchanges
between systems.
If the system is being used to perform a network troubleshooting function, the use of these
tools must be documented with the Information Systems Security Manager (ISSM) and restricted
to only authorized personnel. Identifiers:
CCE-83996-9 References:
1, 11, 14, 3, 9, APO11.06, APO12.06, BAI03.10, BAI09.01, BAI09.02, BAI09.03, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.05, DSS04.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.2.3.4, 4.3.3.3.7, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, SR 7.8, A.11.1.2, A.11.2.4, A.11.2.5, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.16.1.6, A.8.1.1, A.8.1.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), CM-7(2), MA-3, DE.DP-5, ID.AM-1, PR.IP-1, PR.MA-1, PR.PT-3, SRG-OS-000480-GPOS-00227 |
File Permissions and Masks
[ref]groupTraditional Unix security relies heavily on file and
directory permissions to prevent unauthorized users from reading or
modifying files to which they should not have access.
Several of the commands in this section search filesystems
for files or directories with certain characteristics, and are
intended to be run on every local partition on a given system.
When the variable PART appears in one of the commands below,
it means that the command is intended to be run repeatedly, with the
name of each local partition substituted for PART in turn.
The following command prints a list of all xfs partitions on the local
system, which is the default filesystem for Red Hat Enterprise Linux 9
installations:
$ mount -t xfs | awk '{print $3}'
For any systems that use a different
local filesystem type, modify this command as appropriate. |
contains 19 rules |
Verify Permissions on Important Files and
Directories
[ref]groupPermissions for many files on a system must be set
restrictively to ensure sensitive information is properly protected.
This section discusses important
permission restrictions which can be verified
to ensure that no harmful discrepancies have
arisen. |
contains 8 rules |
Verify File Permissions Within Some Important Directories
[ref]groupSome directories contain files whose confidentiality or integrity
is notably important and may also be susceptible to misconfiguration over time, particularly if
unpackaged software is installed. As such,
an argument exists to verify that files' permissions within these directories remain
configured correctly and restrictively. |
contains 4 rules |
Verify that System Executables Have Root Ownership
[ref]ruleSystem executables are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/libexec
/usr/local/bin
/usr/local/sbin
/usr/sbin
All files in these directories should be owned by the root user.
If any file FILE in these directories is found
to be owned by a user other than root, correct its ownership with the
following command:
$ sudo chown root FILE Rationale:System binaries are executed by privileged users as well as system services,
and restrictive permissions are necessary to ensure that their
execution of these programs cannot be co-opted. Identifiers:
CCE-83908-4 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001499, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-5(6), CM-5(6).1, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000259-GPOS-00100 Remediation Shell script: (show)
find /bin/ \
/usr/bin/ \
/usr/local/bin/ \
/sbin/ \
/usr/sbin/ \
/usr/local/sbin/ \
/usr/libexec \
\! -user root -execdir chown root {} \;
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list of system executables without root ownership
command: find /bin/ /usr/bin/ /usr/local/bin/ /sbin/ /usr/sbin/ /usr/local/sbin/
/usr/libexec \! -user root
register: no_root_system_executables
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-83908-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_ownership_binary_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set ownership to root of system executables
file:
path: '{{ item }}'
owner: root
with_items: '{{ no_root_system_executables.stdout_lines }}'
when: no_root_system_executables.stdout_lines | length > 0
tags:
- CCE-83908-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_ownership_binary_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that Shared Library Files Have Root Ownership
[ref]ruleSystem-wide shared library files, which are linked to executables
during process load time or run time, are stored in the following directories
by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are also
stored in /lib/modules . All files in these directories should be
owned by the root user. If the directory, or any file in these
directories, is found to be owned by a user other than root correct its
ownership with the following command:
$ sudo chown root FILE Rationale:Files from shared library directories are loaded into the address
space of processes (including privileged ones) or of the kernel itself at
runtime. Proper ownership is necessary to protect the integrity of the system. Identifiers:
CCE-83907-6 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001499, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-5(6), CM-5(6).1, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000259-GPOS-00100 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
find /lib/ -type f ! -uid 0 -regex '^.*$' -exec chown 0 {} \;
find /lib64/ -type f ! -uid 0 -regex '^.*$' -exec chown 0 {} \;
find /usr/lib/ -type f ! -uid 0 -regex '^.*$' -exec chown 0 {} \;
find /usr/lib64/ -type f ! -uid 0 -regex '^.*$' -exec chown 0 {} \;
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Find /lib/ file(s) matching ^.*$ recursively
command: find -H /lib/ -type f ! -uid 0 -regex "^.*$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-83907-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_ownership_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner on /lib/ file(s) matching ^.*$
file:
path: '{{ item }}'
owner: '0'
state: file
with_items:
- '{{ files_found.stdout_lines }}'
tags:
- CCE-83907-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_ownership_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Find /lib64/ file(s) matching ^.*$ recursively
command: find -H /lib64/ -type f ! -uid 0 -regex "^.*$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-83907-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_ownership_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner on /lib64/ file(s) matching ^.*$
file:
path: '{{ item }}'
owner: '0'
state: file
with_items:
- '{{ files_found.stdout_lines }}'
tags:
- CCE-83907-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_ownership_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Find /usr/lib/ file(s) matching ^.*$ recursively
command: find -H /usr/lib/ -type f ! -uid 0 -regex "^.*$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-83907-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_ownership_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner on /usr/lib/ file(s) matching ^.*$
file:
path: '{{ item }}'
owner: '0'
state: file
with_items:
- '{{ files_found.stdout_lines }}'
tags:
- CCE-83907-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_ownership_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Find /usr/lib64/ file(s) matching ^.*$ recursively
command: find -H /usr/lib64/ -type f ! -uid 0 -regex "^.*$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-83907-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_ownership_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner on /usr/lib64/ file(s) matching ^.*$
file:
path: '{{ item }}'
owner: '0'
state: file
with_items:
- '{{ files_found.stdout_lines }}'
tags:
- CCE-83907-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_ownership_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Verify that System Executables Have Restrictive Permissions
[ref]ruleSystem executables are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/libexec
/usr/local/bin
/usr/local/sbin
/usr/sbin
All files in these directories should not be group-writable or world-writable.
If any file FILE in these directories is found
to be group-writable or world-writable, correct its permission with the
following command:
$ sudo chmod go-w FILE Rationale:System binaries are executed by privileged users, as well as system services,
and restrictive permissions are necessary to ensure execution of these programs
cannot be co-opted. Identifiers:
CCE-83911-8 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001499, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-5(6), CM-5(6).1, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000259-GPOS-00100 Remediation Shell script: (show)
DIRS="/bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin /usr/libexec"
for dirPath in $DIRS; do
find "$dirPath" -perm /022 -exec chmod go-w '{}' \;
done
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list of world and group writable system executables
command: find /bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin /usr/libexec
-perm /022 -type f
register: world_writable_library_files
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-83911-8
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_permissions_binary_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remove world/group writability of system executables
file:
path: '{{ item }}'
mode: go-w
with_items: '{{ world_writable_library_files.stdout_lines }}'
when: world_writable_library_files.stdout_lines | length > 0
tags:
- CCE-83911-8
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_permissions_binary_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that Shared Library Files Have Restrictive Permissions
[ref]ruleSystem-wide shared library files, which are linked to executables
during process load time or run time, are stored in the following directories
by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are
stored in /lib/modules . All files in these directories
should not be group-writable or world-writable. If any file in these
directories is found to be group-writable or world-writable, correct
its permission with the following command:
$ sudo chmod go-w FILE Rationale:Files from shared library directories are loaded into the address
space of processes (including privileged ones) or of the kernel itself at
runtime. Restrictive permissions are necessary to protect the integrity of the system. Identifiers:
CCE-83909-2 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001499, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), CM-5(6), CM-5(6).1, AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000259-GPOS-00100 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
find -H /lib/ -perm /u+s,g+ws,o+wt -type f -regex '^.*$' -exec chmod u-s,g-ws,o-wt {} \;
find -H /lib64/ -perm /u+s,g+ws,o+wt -type f -regex '^.*$' -exec chmod u-s,g-ws,o-wt {} \;
find -H /usr/lib/ -perm /u+s,g+ws,o+wt -type f -regex '^.*$' -exec chmod u-s,g-ws,o-wt {} \;
find -H /usr/lib64/ -perm /u+s,g+ws,o+wt -type f -regex '^.*$' -exec chmod u-s,g-ws,o-wt {} \;
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Find /lib/ file(s) recursively
command: find -H /lib/ -perm /u+s,g+ws,o+wt -type f -regex "^.*$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-83909-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /lib/ file(s)
file:
path: '{{ item }}'
mode: u-s,g-ws,o-wt
state: file
with_items:
- '{{ files_found.stdout_lines }}'
tags:
- CCE-83909-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Find /lib64/ file(s) recursively
command: find -H /lib64/ -perm /u+s,g+ws,o+wt -type f -regex "^.*$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-83909-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /lib64/ file(s)
file:
path: '{{ item }}'
mode: u-s,g-ws,o-wt
state: file
with_items:
- '{{ files_found.stdout_lines }}'
tags:
- CCE-83909-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Find /usr/lib/ file(s) recursively
command: find -H /usr/lib/ -perm /u+s,g+ws,o+wt -type f -regex "^.*$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-83909-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /usr/lib/ file(s)
file:
path: '{{ item }}'
mode: u-s,g-ws,o-wt
state: file
with_items:
- '{{ files_found.stdout_lines }}'
tags:
- CCE-83909-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Find /usr/lib64/ file(s) recursively
command: find -H /usr/lib64/ -perm /u+s,g+ws,o+wt -type f -regex "^.*$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-83909-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /usr/lib64/ file(s)
file:
path: '{{ item }}'
mode: u-s,g-ws,o-wt
state: file
with_items:
- '{{ files_found.stdout_lines }}'
tags:
- CCE-83909-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_library_dirs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Verify that All World-Writable Directories Have Sticky Bits Set
[ref]ruleWhen the so-called 'sticky bit' is set on a directory,
only the owner of a given file may remove that file from the
directory. Without the sticky bit, any user with write access to a
directory may remove any file in the directory. Setting the sticky
bit prevents users from removing each other's files. In cases where
there is no reason for a directory to be world-writable, a better
solution is to remove that permission rather than to set the sticky
bit. However, if a directory is used by a particular application,
consult that application's documentation instead of blindly
changing modes.
To set the sticky bit on a world-writable directory DIR, run the
following command:
$ sudo chmod +t DIR Rationale:Failing to set the sticky bit on public directories allows unauthorized
users to delete files in the directory structure.
The only authorized public directories are those temporary directories
supplied with the system, or those designed to be temporary file
repositories. The setting is normally reserved for directories used by the
system, by users for temporary file storage (such as /tmp ), and
for directories requiring global read/write access. Identifiers:
CCE-83895-3 References:
BP28(R40), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001090, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000138-GPOS-00069 Remediation Shell script: (show)
df --local -P | awk '{if (NR!=1) print $6}' \
| xargs -I '{}' find '{}' -xdev -type d \
\( -perm -0002 -a ! -perm -1000 \) 2>/dev/null \
| xargs chmod a+t
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Get all world-writable directories with no sticky bits set
shell: |
set -o pipefail
df --local -P | awk '{if (NR!=1) print $6}' | xargs -I '{}' find '{}' -xdev -type d \( -perm -0002 -a ! -perm -1000 \) 2>/dev/null
register: dir_output
tags:
- CCE-83895-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: ensure sticky bit is set
file:
path: '{{ item }}'
mode: a+t
with_items:
- '{{ dir_output.stdout_lines }}'
tags:
- CCE-83895-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure All SGID Executables Are Authorized
[ref]ruleThe SGID (set group id) bit should be set only on files that were
installed via authorized means. A straightforward means of identifying
unauthorized SGID files is determine if any were not installed as part of an
RPM package, which is cryptographically verified. Investigate the origin
of any unpackaged SGID files.
This configuration check considers authorized SGID files which were installed via RPM.
It is assumed that when an individual has sudo access to install an RPM
and all packages are signed with an organizationally-recognized GPG key,
the software should be considered an approved package on the system.
Any SGID file not deployed through an RPM will be flagged for further review. Rationale:Executable files with the SGID permission run with the privileges of
the owner of the file. SGID files of uncertain provenance could allow for
unprivileged users to elevate privileges. The presence of these files should be
strictly controlled on the system. Identifiers:
CCE-83901-9 References:
BP28(R37), BP28(R38), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5 |
Ensure All SUID Executables Are Authorized
[ref]ruleThe SUID (set user id) bit should be set only on files that were
installed via authorized means. A straightforward means of identifying
unauthorized SUID files is determine if any were not installed as part of an
RPM package, which is cryptographically verified. Investigate the origin
of any unpackaged SUID files.
This configuration check considers authorized SUID files which were installed via RPM.
It is assumed that when an individual has sudo access to install an RPM
and all packages are signed with an organizationally-recognized GPG key,
the software should be considered an approved package on the system.
Any SUID file not deployed through an RPM will be flagged for further review. Rationale:Executable files with the SUID permission run with the privileges of
the owner of the file. SUID files of uncertain provenance could allow for
unprivileged users to elevate privileges. The presence of these files should be
strictly controlled on the system. Identifiers:
CCE-83897-9 References:
BP28(R37), BP28(R38), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5 |
Ensure No World-Writable Files Exist
[ref]ruleIt is generally a good idea to remove global (other) write
access to a file when it is discovered. However, check with
documentation for specific applications before making changes.
Also, monitor for recurring world-writable files, as these may be
symptoms of a misconfigured application or user account. Finally,
this applies to real files and not virtual files that are a part of
pseudo file systems such as sysfs or procfs . Rationale:Data in world-writable files can be modified by any
user on the system. In almost all circumstances, files can be
configured using a combination of user and group permissions to
support whatever legitimate access is needed without the risk
caused by world-writable files. Identifiers:
CCE-83902-7 References:
BP28(R40), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5 Remediation Shell script: (show)
find / -xdev -type f -perm -002 -exec chmod o-w {} \;
|
Restrict Partition Mount Options
[ref]groupSystem partitions can be mounted with certain options
that limit what files on those partitions can do. These options
are set in the /etc/fstab configuration file, and can be
used to make certain types of malicious behavior more difficult. |
contains 3 rules |
Add nodev Option to /dev/shm
[ref]ruleThe nodev mount option can be used to prevent creation of device
files in /dev/shm . Legitimate character and block devices should
not exist within temporary directories like /dev/shm .
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm . Rationale:The only legitimate location for device files is the /dev directory
located on the root partition. The only exception to this is chroot jails. Identifiers:
CCE-83881-3 References:
11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /dev/shm)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo "tmpfs /dev/shm tmpfs defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nodev")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
fi
if mkdir -p "/dev/shm"; then
if mountpoint -q "/dev/shm"; then
mount -o remount --target "/dev/shm"
else
mount --target "/dev/shm"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Strategy: | configure |
---|
- name: 'Add nodev Option to /dev/shm: Check information associated to mountpoint'
command: findmnt '/dev/shm'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83881-3
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nodev
- no_reboot_needed
- name: 'Add nodev Option to /dev/shm: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-83881-3
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nodev
- no_reboot_needed
- name: 'Add nodev Option to /dev/shm: If /dev/shm not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /dev/shm
- tmpfs
- tmpfs
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-83881-3
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nodev
- no_reboot_needed
- name: 'Add nodev Option to /dev/shm: Make sure nodev option is part of the to /dev/shm
options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nodev''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "nodev" not in mount_info.options
tags:
- CCE-83881-3
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nodev
- no_reboot_needed
- name: 'Add nodev Option to /dev/shm: Ensure /dev/shm is mounted with nodev option'
mount:
path: /dev/shm
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or (""
| length == 0)
tags:
- CCE-83881-3
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nodev
- no_reboot_needed
|
Add noexec Option to /dev/shm
[ref]ruleThe noexec mount option can be used to prevent binaries
from being executed out of /dev/shm .
It can be dangerous to allow the execution of binaries
from world-writable temporary storage directories such as /dev/shm .
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm . Rationale:Allowing users to execute binaries from world-writable directories
such as /dev/shm can expose the system to potential compromise. Identifiers:
CCE-83857-3 References:
11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /dev/shm)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|noexec)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo "tmpfs /dev/shm tmpfs defaults,${previous_mount_opts}noexec 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "noexec")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,noexec|" /etc/fstab
fi
if mkdir -p "/dev/shm"; then
if mountpoint -q "/dev/shm"; then
mount -o remount --target "/dev/shm"
else
mount --target "/dev/shm"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Strategy: | configure |
---|
- name: 'Add noexec Option to /dev/shm: Check information associated to mountpoint'
command: findmnt '/dev/shm'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83857-3
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_noexec
- no_reboot_needed
- name: 'Add noexec Option to /dev/shm: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-83857-3
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_noexec
- no_reboot_needed
- name: 'Add noexec Option to /dev/shm: If /dev/shm not mounted, craft mount_info
manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /dev/shm
- tmpfs
- tmpfs
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-83857-3
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_noexec
- no_reboot_needed
- name: 'Add noexec Option to /dev/shm: Make sure noexec option is part of the to
/dev/shm options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',noexec''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "noexec" not in mount_info.options
tags:
- CCE-83857-3
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_noexec
- no_reboot_needed
- name: 'Add noexec Option to /dev/shm: Ensure /dev/shm is mounted with noexec option'
mount:
path: /dev/shm
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or (""
| length == 0)
tags:
- CCE-83857-3
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_noexec
- no_reboot_needed
|
Add nosuid Option to /dev/shm
[ref]ruleThe nosuid mount option can be used to prevent execution
of setuid programs in /dev/shm . The SUID and SGID permissions should not
be required in these world-writable directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm . Rationale:The presence of SUID and SGID executables should be tightly controlled. Users
should not be able to execute SUID or SGID binaries from temporary storage partitions. Identifiers:
CCE-83891-2 References:
11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /dev/shm)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo "tmpfs /dev/shm tmpfs defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nosuid")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
fi
if mkdir -p "/dev/shm"; then
if mountpoint -q "/dev/shm"; then
mount -o remount --target "/dev/shm"
else
mount --target "/dev/shm"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /dev/shm: Check information associated to mountpoint'
command: findmnt '/dev/shm'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83891-2
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /dev/shm: Create mount_info dictionary variable'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-83891-2
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /dev/shm: If /dev/shm not mounted, craft mount_info
manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /dev/shm
- tmpfs
- tmpfs
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-83891-2
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /dev/shm: Make sure nosuid option is part of the to
/dev/shm options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "nosuid" not in mount_info.options
tags:
- CCE-83891-2
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /dev/shm: Ensure /dev/shm is mounted with nosuid option'
mount:
path: /dev/shm
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or (""
| length == 0)
tags:
- CCE-83891-2
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_dev_shm_nosuid
- no_reboot_needed
|
Restrict Programs from Dangerous Execution Patterns
[ref]groupThe recommendations in this section are designed to
ensure that the system's features to protect against potentially
dangerous program execution are activated.
These protections are applied at the system initialization or
kernel level, and defend against certain types of badly-configured
or compromised programs. |
contains 8 rules |
Enable ExecShield
[ref]groupExecShield describes kernel features that provide
protection against exploitation of memory corruption errors such as buffer
overflows. These features include random placement of the stack and other
memory regions, prevention of execution in memory that should only hold data,
and special handling of text buffers. These protections are enabled by default
on 32-bit systems and controlled through sysctl variables
kernel.exec-shield and kernel.randomize_va_space . On the latest
64-bit systems, kernel.exec-shield cannot be enabled or disabled with
sysctl . |
contains 3 rules |
Enable ExecShield via sysctl
[ref]ruleBy default on Red Hat Enterprise Linux 7 64-bit systems, ExecShield is
enabled and can only be disabled if the hardware does not support
ExecShield or is disabled in /etc/default/grub . For Red Hat
Enterprise Linux 7 32-bit systems, sysctl can be used to enable
ExecShield. Rationale:ExecShield uses the segmentation feature on all x86 systems to prevent
execution in memory higher than a certain address. It writes an address as
a limit in the code segment descriptor, to control where code can be
executed, on a per-process basis. When the kernel places a process's memory
regions such as the stack and heap higher than this address, the hardware
prevents execution in that address range. This is enabled by default on the
latest Red Hat and Fedora systems if supported by the hardware. Identifiers:
CCE-83970-4 References:
BP28(R9), 12, 15, 8, APO13.01, DSS05.02, 3.1.7, CCI-002530, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.13.1.1, A.13.2.1, A.14.1.3, SC-39, CM-6(a), PR.PT-4, SRG-OS-000433-GPOS-00192 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ "$(getconf LONG_BIT)" = "32" ] ; then
#
# Set runtime for kernel.exec-shield
#
sysctl -q -n -w kernel.exec-shield=1
#
# If kernel.exec-shield present in /etc/sysctl.conf, change value to "1"
# else, add "kernel.exec-shield = 1" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.exec-shield")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.exec-shield\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^kernel.exec-shield\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83970-4"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
fi
if [ "$(getconf LONG_BIT)" = "64" ] ; then
if grep --silent noexec /boot/grub2/grub*.cfg ; then
sed -i "s/noexec.*//g" /etc/default/grub
sed -i "s/noexec.*//g" /etc/grub.d/*
grub2-mkconfig -o "/boot/grub2"/grub*.cfg
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Restrict Exposed Kernel Pointer Addresses Access
[ref]ruleTo set the runtime status of the kernel.kptr_restrict kernel parameter, run the following command: $ sudo sysctl -w kernel.kptr_restrict=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.kptr_restrict = 1 Rationale:Exposing kernel pointers (through procfs or seq_printf() ) exposes
kernel writeable structures that can contain functions pointers. If a write vulnereability occurs
in the kernel allowing a write access to any of this structure, the kernel can be compromise. This
option disallow any program withtout the CAP_SYSLOG capability from getting the kernel pointers addresses,
replacing them with 0. Identifiers:
CCE-83972-0 References:
BP28(R23), CCI-002824, CCI-000366, CIP-002-5 R1.1, CIP-002-5 R1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 4.1, CIP-004-6 4.2, CIP-004-6 R2.2.3, CIP-004-6 R2.2.4, CIP-004-6 R2.3, CIP-004-6 R4, CIP-005-6 R1, CIP-005-6 R1.1, CIP-005-6 R1.2, CIP-007-3 R3, CIP-007-3 R3.1, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R8.4, CIP-009-6 R.1.1, CIP-009-6 R4, SC-30, SC-30(2), SC-30(5), CM-6(a), SRG-OS-000132-GPOS-00067, SRG-OS-000433-GPOS-00192, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of kernel.kptr_restrict from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf ; do
matching_list=$(grep -P '^(?!#).*[\s]+kernel.kptr_restrict.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "kernel.kptr_restrict" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
sysctl_kernel_kptr_restrict_value='1'
#
# Set runtime for kernel.kptr_restrict
#
/sbin/sysctl -q -n -w kernel.kptr_restrict="$sysctl_kernel_kptr_restrict_value"
#
# If kernel.kptr_restrict present in /etc/sysctl.conf, change value to appropriate value
# else, add "kernel.kptr_restrict = value" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.kptr_restrict")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_kernel_kptr_restrict_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.kptr_restrict\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^kernel.kptr_restrict\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83972-0"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths: /etc/sysctl.d/
contains: ^[\s]*kernel.kptr_restrict.*$
patterns: '*.conf'
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83972-0
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- NIST-800-53-SC-30(5)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_kptr_restrict
- name: Comment out any occurrences of kernel.kptr_restrict from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item }}'
regexp: ^[\s]*kernel.kptr_restrict
replace: '#kernel.kptr_restrict'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83972-0
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- NIST-800-53-SC-30(5)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_kptr_restrict
- name: XCCDF Value sysctl_kernel_kptr_restrict_value # promote to variable
set_fact:
sysctl_kernel_kptr_restrict_value: !!str 1
tags:
- always
- name: Ensure sysctl kernel.kptr_restrict is set
sysctl:
name: kernel.kptr_restrict
value: '{{ sysctl_kernel_kptr_restrict_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83972-0
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- NIST-800-53-SC-30(5)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_kptr_restrict
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,kernel.kptr_restrict%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_kernel_kptr_restrict.conf
overwrite: true
|
Enable Randomized Layout of Virtual Address Space
[ref]ruleTo set the runtime status of the kernel.randomize_va_space kernel parameter, run the following command: $ sudo sysctl -w kernel.randomize_va_space=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.randomize_va_space = 2 Rationale:Address space layout randomization (ASLR) makes it more difficult for an
attacker to predict the location of attack code they have introduced into a
process's address space during an attempt at exploitation. Additionally,
ASLR makes it more difficult for an attacker to know the location of
existing code in order to re-purpose it using return oriented programming
(ROP) techniques. Identifiers:
CCE-83971-2 References:
BP28(R23), 3.1.7, CCI-000366, CCI-002824, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), CIP-002-5 R1.1, CIP-002-5 R1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 4.1, CIP-004-6 4.2, CIP-004-6 R2.2.3, CIP-004-6 R2.2.4, CIP-004-6 R2.3, CIP-004-6 R4, CIP-005-6 R1, CIP-005-6 R1.1, CIP-005-6 R1.2, CIP-007-3 R3, CIP-007-3 R3.1, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R8.4, CIP-009-6 R.1.1, CIP-009-6 R4, SC-30, SC-30(2), CM-6(a), SRG-OS-000433-GPOS-00193, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of kernel.randomize_va_space from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf ; do
matching_list=$(grep -P '^(?!#).*[\s]+kernel.randomize_va_space.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "kernel.randomize_va_space" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for kernel.randomize_va_space
#
/sbin/sysctl -q -n -w kernel.randomize_va_space="2"
#
# If kernel.randomize_va_space present in /etc/sysctl.conf, change value to "2"
# else, add "kernel.randomize_va_space = 2" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.randomize_va_space")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "2"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.randomize_va_space\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^kernel.randomize_va_space\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83971-2"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths: /etc/sysctl.d/
contains: ^[\s]*kernel.randomize_va_space.*$
patterns: '*.conf'
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83971-2
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
- name: Comment out any occurrences of kernel.randomize_va_space from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item }}'
regexp: ^[\s]*kernel.randomize_va_space
replace: '#kernel.randomize_va_space'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83971-2
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
- name: Ensure sysctl kernel.randomize_va_space is set to 2
sysctl:
name: kernel.randomize_va_space
value: '2'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83971-2
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,kernel.randomize_va_space%3D2%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_kernel_randomize_va_space.conf
overwrite: true
|
Restrict Access to Kernel Message Buffer
[ref]ruleTo set the runtime status of the kernel.dmesg_restrict kernel parameter, run the following command: $ sudo sysctl -w kernel.dmesg_restrict=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.dmesg_restrict = 1 Rationale:Unprivileged access to the kernel syslog can expose sensitive kernel
address information. Identifiers:
CCE-83952-2 References:
BP28(R23), 3.1.5, CCI-001314, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), SI-11(a), SI-11(b), SRG-OS-000132-GPOS-00067, SRG-OS-000138-GPOS-00069 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of kernel.dmesg_restrict from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf ; do
matching_list=$(grep -P '^(?!#).*[\s]+kernel.dmesg_restrict.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "kernel.dmesg_restrict" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for kernel.dmesg_restrict
#
/sbin/sysctl -q -n -w kernel.dmesg_restrict="1"
#
# If kernel.dmesg_restrict present in /etc/sysctl.conf, change value to "1"
# else, add "kernel.dmesg_restrict = 1" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.dmesg_restrict")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.dmesg_restrict\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^kernel.dmesg_restrict\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83952-2"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths: /etc/sysctl.d/
contains: ^[\s]*kernel.dmesg_restrict.*$
patterns: '*.conf'
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83952-2
- NIST-800-171-3.1.5
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- disable_strategy
- low_complexity
- low_severity
- medium_disruption
- reboot_required
- sysctl_kernel_dmesg_restrict
- name: Comment out any occurrences of kernel.dmesg_restrict from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item }}'
regexp: ^[\s]*kernel.dmesg_restrict
replace: '#kernel.dmesg_restrict'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83952-2
- NIST-800-171-3.1.5
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- disable_strategy
- low_complexity
- low_severity
- medium_disruption
- reboot_required
- sysctl_kernel_dmesg_restrict
- name: Ensure sysctl kernel.dmesg_restrict is set to 1
sysctl:
name: kernel.dmesg_restrict
value: '1'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83952-2
- NIST-800-171-3.1.5
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- disable_strategy
- low_complexity
- low_severity
- medium_disruption
- reboot_required
- sysctl_kernel_dmesg_restrict
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,kernel.dmesg_restrict%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_kernel_dmesg_restrict.conf
overwrite: true
|
Disable Kernel Image Loading
[ref]ruleTo set the runtime status of the kernel.kexec_load_disabled kernel parameter, run the following command: $ sudo sysctl -w kernel.kexec_load_disabled=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.kexec_load_disabled = 1 Rationale:Disabling kexec_load allows greater control of the kernel memory.
It makes it impossible to load another kernel image after it has been disabled.
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of kernel.kexec_load_disabled from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf ; do
matching_list=$(grep -P '^(?!#).*[\s]+kernel.kexec_load_disabled.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "kernel.kexec_load_disabled" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for kernel.kexec_load_disabled
#
/sbin/sysctl -q -n -w kernel.kexec_load_disabled="1"
#
# If kernel.kexec_load_disabled present in /etc/sysctl.conf, change value to "1"
# else, add "kernel.kexec_load_disabled = 1" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.kexec_load_disabled")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.kexec_load_disabled\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^kernel.kexec_load_disabled\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83954-8"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths: /etc/sysctl.d/
contains: ^[\s]*kernel.kexec_load_disabled.*$
patterns: '*.conf'
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83954-8
- NIST-800-53-CM-6
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_kexec_load_disabled
- name: Comment out any occurrences of kernel.kexec_load_disabled from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item }}'
regexp: ^[\s]*kernel.kexec_load_disabled
replace: '#kernel.kexec_load_disabled'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83954-8
- NIST-800-53-CM-6
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_kexec_load_disabled
- name: Ensure sysctl kernel.kexec_load_disabled is set to 1
sysctl:
name: kernel.kexec_load_disabled
value: '1'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83954-8
- NIST-800-53-CM-6
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_kexec_load_disabled
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,kernel.kexec_load_disabled%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_kernel_kexec_load_disabled.conf
overwrite: true
|
Disable Access to Network bpf() Syscall From Unprivileged Processes
[ref]ruleTo set the runtime status of the kernel.unprivileged_bpf_disabled kernel parameter, run the following command: $ sudo sysctl -w kernel.unprivileged_bpf_disabled=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.unprivileged_bpf_disabled = 1 Rationale:Loading and accessing the packet filters programs and maps using the bpf()
syscall has the potential of revealing sensitive information about the kernel state. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of kernel.unprivileged_bpf_disabled from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf ; do
matching_list=$(grep -P '^(?!#).*[\s]+kernel.unprivileged_bpf_disabled.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "kernel.unprivileged_bpf_disabled" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for kernel.unprivileged_bpf_disabled
#
/sbin/sysctl -q -n -w kernel.unprivileged_bpf_disabled="1"
#
# If kernel.unprivileged_bpf_disabled present in /etc/sysctl.conf, change value to "1"
# else, add "kernel.unprivileged_bpf_disabled = 1" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.unprivileged_bpf_disabled")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.unprivileged_bpf_disabled\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^kernel.unprivileged_bpf_disabled\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83957-1"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths: /etc/sysctl.d/
contains: ^[\s]*kernel.unprivileged_bpf_disabled.*$
patterns: '*.conf'
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83957-1
- NIST-800-53-AC-6
- NIST-800-53-SC-7(10)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_unprivileged_bpf_disabled
- name: Comment out any occurrences of kernel.unprivileged_bpf_disabled from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item }}'
regexp: ^[\s]*kernel.unprivileged_bpf_disabled
replace: '#kernel.unprivileged_bpf_disabled'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83957-1
- NIST-800-53-AC-6
- NIST-800-53-SC-7(10)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_unprivileged_bpf_disabled
- name: Ensure sysctl kernel.unprivileged_bpf_disabled is set to 1
sysctl:
name: kernel.unprivileged_bpf_disabled
value: '1'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83957-1
- NIST-800-53-AC-6
- NIST-800-53-SC-7(10)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_unprivileged_bpf_disabled
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,kernel.unprivileged_bpf_disabled%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_kernel_unprivileged_bpf_disabled.conf
overwrite: true
|
Restrict usage of ptrace to descendant processes
[ref]ruleTo set the runtime status of the kernel.yama.ptrace_scope kernel parameter, run the following command: $ sudo sysctl -w kernel.yama.ptrace_scope=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.yama.ptrace_scope = 1 Rationale:Unrestricted usage of ptrace allows compromised binaries to run ptrace
on another processes of the user. Like this, the attacker can steal
sensitive information from the target processes (e.g. SSH sessions, web browser, ...)
without any additional assistance from the user (i.e. without resorting to phishing).
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of kernel.yama.ptrace_scope from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf ; do
matching_list=$(grep -P '^(?!#).*[\s]+kernel.yama.ptrace_scope.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "kernel.yama.ptrace_scope" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for kernel.yama.ptrace_scope
#
/sbin/sysctl -q -n -w kernel.yama.ptrace_scope="1"
#
# If kernel.yama.ptrace_scope present in /etc/sysctl.conf, change value to "1"
# else, add "kernel.yama.ptrace_scope = 1" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.yama.ptrace_scope")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.yama.ptrace_scope\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^kernel.yama.ptrace_scope\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83965-4"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths: /etc/sysctl.d/
contains: ^[\s]*kernel.yama.ptrace_scope.*$
patterns: '*.conf'
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83965-4
- NIST-800-53-SC-7(10)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_yama_ptrace_scope
- name: Comment out any occurrences of kernel.yama.ptrace_scope from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item }}'
regexp: ^[\s]*kernel.yama.ptrace_scope
replace: '#kernel.yama.ptrace_scope'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83965-4
- NIST-800-53-SC-7(10)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_yama_ptrace_scope
- name: Ensure sysctl kernel.yama.ptrace_scope is set to 1
sysctl:
name: kernel.yama.ptrace_scope
value: '1'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83965-4
- NIST-800-53-SC-7(10)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_yama_ptrace_scope
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,kernel.yama.ptrace_scope%3D1%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_kernel_yama_ptrace_scope.conf
overwrite: true
|
Harden the operation of the BPF just-in-time compiler
[ref]ruleTo set the runtime status of the net.core.bpf_jit_harden kernel parameter, run the following command: $ sudo sysctl -w net.core.bpf_jit_harden=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.core.bpf_jit_harden = 2 Rationale:When hardened, the extended Berkeley Packet Filter just-in-time compiler
will randomize any kernel addresses in the BPF programs and maps,
and will not expose the JIT addresses in /proc/kallsyms . Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.core.bpf_jit_harden from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf ; do
matching_list=$(grep -P '^(?!#).*[\s]+net.core.bpf_jit_harden.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "net.core.bpf_jit_harden" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set runtime for net.core.bpf_jit_harden
#
/sbin/sysctl -q -n -w net.core.bpf_jit_harden="2"
#
# If net.core.bpf_jit_harden present in /etc/sysctl.conf, change value to "2"
# else, add "net.core.bpf_jit_harden = 2" to /etc/sysctl.conf
#
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/sysctl.conf"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.core.bpf_jit_harden")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "2"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.core.bpf_jit_harden\\>" "/etc/sysctl.conf"; then
"${sed_command[@]}" "s/^net.core.bpf_jit_harden\\>.*/$formatted_output/gi" "/etc/sysctl.conf"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-83966-2"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/sysctl.conf" >> "/etc/sysctl.conf"
printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths: /etc/sysctl.d/
contains: ^[\s]*net.core.bpf_jit_harden.*$
patterns: '*.conf'
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83966-2
- NIST-800-53-CM-6
- NIST-800-53-SC-7(10)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_core_bpf_jit_harden
- name: Comment out any occurrences of net.core.bpf_jit_harden from /etc/sysctl.d/*.conf
files
replace:
path: '{{ item }}'
regexp: ^[\s]*net.core.bpf_jit_harden
replace: '#net.core.bpf_jit_harden'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83966-2
- NIST-800-53-CM-6
- NIST-800-53-SC-7(10)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_core_bpf_jit_harden
- name: Ensure sysctl net.core.bpf_jit_harden is set to 2
sysctl:
name: net.core.bpf_jit_harden
value: '2'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83966-2
- NIST-800-53-CM-6
- NIST-800-53-SC-7(10)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_core_bpf_jit_harden
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,net.core.bpf_jit_harden%3D2%0A
mode: 0644
path: /etc/sysctl.d/75-sysctl_net_core_bpf_jit_harden.conf
overwrite: true
|
SELinux
[ref]groupSELinux is a feature of the Linux kernel which can be
used to guard against misconfigured or compromised programs.
SELinux enforces the idea that programs should be limited in what
files they can access and what actions they can take.
The default SELinux policy, as configured on Red Hat Enterprise Linux 9, has been
sufficiently developed and debugged that it should be usable on
almost any system with minimal configuration and a small
amount of system administrator training. This policy prevents
system services - including most of the common network-visible
services such as mail servers, FTP servers, and DNS servers - from
accessing files which those services have no valid reason to
access. This action alone prevents a huge amount of possible damage
from network attacks against services, from trojaned software, and
so forth.
This guide recommends that SELinux be enabled using the
default (targeted) policy on every Red Hat Enterprise Linux 9 system, unless that
system has unusual requirements which make a stronger policy
appropriate. |
contains 3 rules |
SELinux - Booleans
[ref]groupEnable or Disable runtime customization of SELinux system policies
without having to reload or recompile the SELinux policy. |
contains 1 rule |
Enable the auditadm_exec_content SELinux Boolean
[ref]ruleBy default, the SELinux boolean auditadm_exec_content is enabled.
If this setting is disabled, it should be enabled.
To enable the auditadm_exec_content SELinux boolean, run the following command:
$ sudo setsebool -P auditadm_exec_content on Rationale:Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_auditadm_exec_content='true'
setsebool -P auditadm_exec_content $var_auditadm_exec_content
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: XCCDF Value var_auditadm_exec_content # promote to variable
set_fact:
var_auditadm_exec_content: !!str true
tags:
- always
- name: Ensure python3-libsemanage installed
package:
name: python3-libsemanage
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84090-0
- NIST-800-171-80424-5
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- sebool_auditadm_exec_content
- name: Set SELinux boolean auditadm_exec_content accordingly
seboolean:
name: auditadm_exec_content
state: '{{ var_auditadm_exec_content }}'
persistent: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84090-0
- NIST-800-171-80424-5
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- sebool_auditadm_exec_content
|
Configure SELinux Policy
[ref]ruleThe SELinux targeted policy is appropriate for
general-purpose desktops and servers, as well as systems in many other roles.
To configure the system to use this policy, add or correct the following line
in /etc/selinux/config :
SELINUXTYPE=targeted
Other policies, such as mls , provide additional security labeling
and greater confinement but are not compatible with many general-purpose
use cases.Rationale:Setting the SELinux policy to targeted or a more specialized policy
ensures the system will confine processes that are likely to be
targeted for exploitation, such as network or system services.
Note: During the development or debugging of SELinux modules, it is common to
temporarily place non-production systems in permissive mode. In such
temporary cases, SELinux policies should be developed, and once work
is completed, the system should be reconfigured to
targeted . Identifiers:
CCE-84074-4 References:
BP28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-GPOS-00199, SRG-OS-000445-VMM-001780 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_selinux_policy_name='targeted'
if [ -e "/etc/selinux/config" ] ; then
LC_ALL=C sed -i "/^SELINUXTYPE=/Id" "/etc/selinux/config"
else
touch "/etc/selinux/config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/selinux/config"
cp "/etc/selinux/config" "/etc/selinux/config.bak"
# Insert at the end of the file
printf '%s\n' "SELINUXTYPE=$var_selinux_policy_name" >> "/etc/selinux/config"
# Clean up after ourselves.
rm "/etc/selinux/config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_selinux_policy_name # promote to variable
set_fact:
var_selinux_policy_name: !!str targeted
tags:
- always
- name: Configure SELinux Policy
block:
- name: Check for duplicate values
lineinfile:
path: /etc/selinux/config
create: false
regexp: ^SELINUXTYPE=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: false
regexp: ^SELINUXTYPE=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: true
regexp: ^SELINUXTYPE=
line: SELINUXTYPE={{ var_selinux_policy_name }}
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84074-4
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- NIST-800-53-AU-9
- NIST-800-53-SC-7(21)
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- selinux_policytype
|
Ensure SELinux State is Enforcing
[ref]ruleThe SELinux state should be set to enforcing at
system boot time. In the file /etc/selinux/config , add or correct the
following line to configure the system to boot into enforcing mode:
SELINUX=enforcing Rationale:Setting the SELinux state to enforcing ensures SELinux is able to confine
potentially compromised processes to the security policy, which is designed to
prevent them from causing damage to the system or further elevating their
privileges. Identifiers:
CCE-84079-3 References:
BP28(R4), BP28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-GPOS-00199, SRG-OS-000445-VMM-001780 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_selinux_state='enforcing'
if [ -e "/etc/selinux/config" ] ; then
LC_ALL=C sed -i "/^SELINUX=/Id" "/etc/selinux/config"
else
touch "/etc/selinux/config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/selinux/config"
cp "/etc/selinux/config" "/etc/selinux/config.bak"
# Insert at the end of the file
printf '%s\n' "SELINUX=$var_selinux_state" >> "/etc/selinux/config"
# Clean up after ourselves.
rm "/etc/selinux/config.bak"
fixfiles onboot
fixfiles -f relabel
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_selinux_state # promote to variable
set_fact:
var_selinux_state: !!str enforcing
tags:
- always
- name: Ensure SELinux State is Enforcing
block:
- name: Check for duplicate values
lineinfile:
path: /etc/selinux/config
create: false
regexp: ^SELINUX=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: false
regexp: ^SELINUX=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: true
regexp: ^SELINUX=
line: SELINUX={{ var_selinux_state }}
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84079-3
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- NIST-800-53-AU-9
- NIST-800-53-SC-7(21)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- selinux_state
|
Services
[ref]groupThe best protection against vulnerable software is running less software. This section describes how to review
the software which Red Hat Enterprise Linux 9 installs on a system and disable software which is not needed. It
then enumerates the software packages installed on a default Red Hat Enterprise Linux 9 system and provides guidance about which
ones can be safely disabled.
Red Hat Enterprise Linux 9 provides a convenient minimal install option that essentially installs the bare necessities for a functional
system. When building Red Hat Enterprise Linux 9 systems, it is highly recommended to select the minimal packages and then build up
the system from there. |
contains 42 rules |
Avahi Server
[ref]groupThe Avahi daemon implements the DNS Service Discovery
and Multicast DNS protocols, which provide service and host
discovery on a network. It allows a system to automatically
identify resources on the network, such as printers or web servers.
This capability is also known as mDNSresponder and is a major part
of Zeroconf networking. |
contains 1 rule |
Disable Avahi Server if Possible
[ref]groupBecause the Avahi daemon service keeps an open network
port, it is subject to network attacks.
Disabling it can reduce the system's vulnerability to such attacks. |
contains 1 rule |
Disable Avahi Server Software
[ref]rule
The avahi-daemon service can be disabled with the following command:
$ sudo systemctl mask --now avahi-daemon.service Rationale:Because the Avahi daemon service keeps an open network
port, it is subject to network attacks. Its functionality
is convenient but is only appropriate if the local network
can be trusted. Identifiers:
CCE-90824-4 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'avahi-daemon.service'
"$SYSTEMCTL_EXEC" disable 'avahi-daemon.service'
"$SYSTEMCTL_EXEC" mask 'avahi-daemon.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^avahi-daemon.socket'; then
"$SYSTEMCTL_EXEC" stop 'avahi-daemon.socket'
"$SYSTEMCTL_EXEC" mask 'avahi-daemon.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'avahi-daemon.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Disable service avahi-daemon
block:
- name: Disable service avahi-daemon
systemd:
name: avahi-daemon.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90824-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_avahi-daemon_disabled
- name: Unit Socket Exists - avahi-daemon.socket
command: systemctl list-unit-files avahi-daemon.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90824-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_avahi-daemon_disabled
- name: Disable socket avahi-daemon
systemd:
name: avahi-daemon.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"avahi-daemon.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-90824-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_avahi-daemon_disabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include disable_avahi-daemon
class disable_avahi-daemon {
service {'avahi-daemon':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: avahi-daemon.service
enabled: false
mask: true
- name: avahi-daemon.socket
enabled: false
mask: true
Remediation script: (show)
[customizations.services]
disabled = ["avahi-daemon"]
|
Application Whitelisting Daemon
[ref]groupFapolicyd (File Access Policy Daemon) implements application whitelisting
to decide file access rights. Applications that are known via a reputation
source are allowed access while unknown applications are not. The daemon
makes use of the kernel's fanotify interface to determine file access rights. |
contains 2 rules |
Install fapolicyd Package
[ref]ruleThe fapolicyd package can be installed with the following command:
$ sudo dnf install fapolicyd Rationale:fapolicyd (File Access Policy Daemon)
implements application whitelisting to decide file access rights. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "fapolicyd" ; then
dnf install -y "fapolicyd"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure fapolicyd is installed
package:
name: fapolicyd
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84224-5
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-4(22)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_fapolicyd_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_fapolicyd
class install_fapolicyd {
package { 'fapolicyd':
ensure => 'installed',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
package --add=fapolicyd
Remediation script: (show)
[[packages]]
name = "fapolicyd"
version = "*"
|
Enable the File Access Policy Service
[ref]ruleThe File Access Policy service should be enabled.
The fapolicyd service can be enabled with the following command:
$ sudo systemctl enable fapolicyd.service Rationale:The fapolicyd service (File Access Policy Daemon)
implements application whitelisting to decide file access rights. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'fapolicyd.service'
"$SYSTEMCTL_EXEC" start 'fapolicyd.service'
"$SYSTEMCTL_EXEC" enable 'fapolicyd.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Enable service fapolicyd
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service fapolicyd
service:
name: fapolicyd
enabled: 'yes'
state: started
masked: 'no'
when:
- '"fapolicyd" in ansible_facts.packages'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84227-8
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-4(22)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_fapolicyd_enabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include enable_fapolicyd
class enable_fapolicyd {
service {'fapolicyd':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
[customizations.services]
enabled = ["fapolicyd"]
|
Network Time Protocol
[ref]groupThe Network Time Protocol is used to manage the system
clock over a network. Computer clocks are not very accurate, so
time will drift unpredictably on unmanaged systems. Central time
protocols can be used both to ensure that time is consistent among
a network of systems, and that their time is consistent with the
outside world.
If every system on a network reliably reports the same time, then it is much
easier to correlate log messages in case of an attack. In addition, a number of
cryptographic protocols (such as Kerberos) use timestamps to prevent certain
types of attacks. If your network does not have synchronized time, these
protocols may be unreliable or even unusable.
Depending on the specifics of the network, global time accuracy may be just as
important as local synchronization, or not very important at all. If your
network is connected to the Internet, using a public timeserver (or one
provided by your enterprise) provides globally accurate timestamps which may be
essential in investigating or responding to an attack which originated outside
of your network.
A typical network setup involves a small number of internal systems operating
as NTP servers, and the remainder obtaining time information from those
internal servers.
There is a choice between the daemons ntpd and chronyd , which
are available from the repositories in the ntp and chrony
packages respectively.
The default chronyd daemon can work well when external time references
are only intermittently accesible, can perform well even when the network is
congested for longer periods of time, can usually synchronize the clock faster
and with better time accuracy, and quickly adapts to sudden changes in the rate
of the clock, for example, due to changes in the temperature of the crystal
oscillator. Chronyd should be considered for all systems which are
frequently suspended or otherwise intermittently disconnected and reconnected
to a network. Mobile and virtual systems for example.
The ntpd NTP daemon fully supports NTP protocol version 4 (RFC 5905),
including broadcast, multicast, manycast clients and servers, and the orphan
mode. It also supports extra authentication schemes based on public-key
cryptography (RFC 5906). The NTP daemon (ntpd ) should be considered
for systems which are normally kept permanently on. Systems which are required
to use broadcast or multicast IP, or to perform authentication of packets with
the Autokey protocol, should consider using ntpd .
Refer to
https://docs.fedoraproject.org/en-US/fedora/rawhide/system-administrators-guide/servers/Configuring_NTP_Using_the_chrony_Suite/
for more detailed comparison of features of chronyd
and ntpd daemon features respectively, and for further guidance how to
choose between the two NTP daemons.
The upstream manual pages at
http://chrony.tuxfamily.org/manual.html for
chronyd and
http://www.ntp.org for ntpd provide additional
information on the capabilities and configuration of each of the NTP daemons. |
contains 3 rules |
The Chrony package is installed
[ref]ruleSystem time should be synchronized between all systems in an environment. This is
typically done by establishing an authoritative time server or set of servers and having all
systems synchronize their clocks to them.
The chrony package can be installed with the following command:
$ sudo dnf install chrony Rationale:Time synchronization is important to support time sensitive security mechanisms like
Kerberos and also ensures log files have consistent time records across the enterprise,
which aids in forensic investigations. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "chrony" ; then
dnf install -y "chrony"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure chrony is installed
package:
name: chrony
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84215-3
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_chrony_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_chrony
class install_chrony {
package { 'chrony':
ensure => 'installed',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
package --add=chrony
Remediation script: (show)
[[packages]]
name = "chrony"
version = "*"
|
The Chronyd service is enabled
[ref]rulechrony is a daemon which implements the Network Time Protocol (NTP) is designed to
synchronize system clocks across a variety of systems and use a source that is highly
accurate. More information on chrony can be found at
http://chrony.tuxfamily.org/.
Chrony can be configured to be a client and/or a server.
To enable Chronyd service, you can run:
# systemctl enable chronyd.service
This recommendation only applies if chrony is in use on the system. Rationale:If chrony is in use on the system proper configuration is vital to ensuring time
synchronization is working properly. Identifiers:
CCE-84217-9 References:
0988, 1405 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'chronyd.service'
"$SYSTEMCTL_EXEC" start 'chronyd.service'
"$SYSTEMCTL_EXEC" enable 'chronyd.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Enable service chronyd
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service chronyd
service:
name: chronyd
enabled: 'yes'
state: started
masked: 'no'
when:
- '"chrony" in ansible_facts.packages'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84217-9
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_chronyd_enabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include enable_chronyd
class enable_chronyd {
service {'chronyd':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
[customizations.services]
enabled = ["chronyd"]
|
A remote time server for Chrony is configured
[ref]ruleChrony is a daemon which implements the Network Time Protocol (NTP). It is designed to
synchronize system clocks across a variety of systems and use a source that is highly
accurate. More information on chrony can be found at
http://chrony.tuxfamily.org/.
Chrony can be configured to be a client and/or a server.
Add or edit server or pool lines to /etc/chrony.conf as appropriate:
server <remote-server>
Multiple servers may be configured.Rationale:If chrony is in use on the system proper configuration is vital to ensuring time
synchronization is working properly. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q chrony; }; then
var_multiple_time_servers='0.pool.ntp.org,1.pool.ntp.org,2.pool.ntp.org,3.pool.ntp.org'
config_file="/etc/chrony.conf"
if ! grep -q '^[\s]*(?:server|pool)[\s]+[\w]+' "$config_file" ; then
if ! grep -q '#[[:space:]]*server' "$config_file" ; then
for server in $(echo "$var_multiple_time_servers" | tr ',' '\n') ; do
printf '\nserver %s' "$server" >> "$config_file"
done
else
sed -i 's/#[ \t]*server/server/g' "$config_file"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-84218-7
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.3
- chronyd_specify_remote_server
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_multiple_time_servers # promote to variable
set_fact:
var_multiple_time_servers: !!str 0.pool.ntp.org,1.pool.ntp.org,2.pool.ntp.org,3.pool.ntp.org
tags:
- always
- name: Detect if chrony is already configured with pools or servers
find:
path: /etc
patterns: chrony.conf
contains: ^[\s]*(?:server|pool)[\s]+[\w]+
register: chrony_servers
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages'
tags:
- CCE-84218-7
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.3
- chronyd_specify_remote_server
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Configure remote time servers
lineinfile:
path: /etc/chrony.conf
line: server {{ item }}
state: present
create: true
loop: '{{ var_multiple_time_servers.split(",") }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages'
- chrony_servers.matched == 0
tags:
- CCE-84218-7
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.3
- chronyd_specify_remote_server
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Obsolete Services
[ref]groupThis section discusses a number of network-visible
services which have historically caused problems for system
security, and for which disabling or severely limiting the service
has been the best available guidance for some time. As a result of
this, many of these services are not installed as part of Red Hat Enterprise Linux 9
by default.
Organizations which are running these services should
switch to more secure equivalents as soon as possible.
If it remains absolutely necessary to run one of
these services for legacy reasons, care should be taken to restrict
the service as much as possible, for instance by configuring host
firewall software such as iptables to restrict access to the
vulnerable service to only those remote hosts which have a known
need to use it. |
contains 10 rules |
Xinetd
[ref]groupThe xinetd service acts as a dedicated listener for some
network services (mostly, obsolete ones) and can be used to provide access
controls and perform some logging. It has been largely obsoleted by other
features, and it is not installed by default. The older Inetd service
is not even available as part of Red Hat Enterprise Linux 9. |
contains 2 rules |
Uninstall xinetd Package
[ref]ruleThe xinetd package can be removed with the following command:
$ sudo dnf erase xinetd Rationale:Removing the xinetd package decreases the risk of the
xinetd service's accidental (or intentional) activation. Identifiers:
CCE-84155-1 References:
BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# CAUTION: This remediation script will remove xinetd
# from the system, and may remove any packages
# that depend on xinetd. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "xinetd" ; then
dnf remove -y "xinetd"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure xinetd is removed
package:
name: xinetd
state: absent
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84155-1
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_xinetd_removed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_xinetd
class remove_xinetd {
package { 'xinetd':
ensure => 'purged',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
package --remove=xinetd
|
Disable xinetd Service
[ref]rule
The xinetd service can be disabled with the following command:
$ sudo systemctl mask --now xinetd.service Rationale:The xinetd service provides a dedicated listener service for some programs,
which is no longer necessary for commonly-used network services. Disabling
it ensures that these uncommon services are not running, and also prevents
attacks against xinetd itself. Identifiers:
CCE-84156-9 References:
11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.4.7, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'xinetd.service'
"$SYSTEMCTL_EXEC" disable 'xinetd.service'
"$SYSTEMCTL_EXEC" mask 'xinetd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^xinetd.socket'; then
"$SYSTEMCTL_EXEC" stop 'xinetd.socket'
"$SYSTEMCTL_EXEC" mask 'xinetd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'xinetd.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Disable service xinetd
block:
- name: Disable service xinetd
systemd:
name: xinetd.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84156-9
- NIST-800-171-3.4.7
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_xinetd_disabled
- name: Unit Socket Exists - xinetd.socket
command: systemctl list-unit-files xinetd.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84156-9
- NIST-800-171-3.4.7
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_xinetd_disabled
- name: Disable socket xinetd
systemd:
name: xinetd.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"xinetd.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-84156-9
- NIST-800-171-3.4.7
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_xinetd_disabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include disable_xinetd
class disable_xinetd {
service {'xinetd':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: xinetd.service
enabled: false
mask: true
- name: xinetd.socket
enabled: false
mask: true
Remediation script: (show)
[customizations.services]
disabled = ["xinetd"]
|
The Network Information Service (NIS), also known as 'Yellow
Pages' (YP), and its successor NIS+ have been made obsolete by
Kerberos, LDAP, and other modern centralized authentication
services. NIS should not be used because it suffers from security
problems inherent in its design, such as inadequate protection of
important authentication information. |
contains 1 rule |
Remove NIS Client
[ref]ruleThe Network Information Service (NIS), formerly known as Yellow Pages,
is a client-server directory service protocol used to distribute system configuration
files. The NIS client (ypbind ) was used to bind a system to an NIS server
and receive the distributed configuration files. Rationale:The NIS service is inherently an insecure system that has been vulnerable
to DOS attacks, buffer overflows and has poor authentication for querying
NIS maps. NIS generally has been replaced by such protocols as Lightweight
Directory Access Protocol (LDAP). It is recommended that the service be
removed. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove ypbind
# from the system, and may remove any packages
# that depend on ypbind. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "ypbind" ; then
dnf remove -y "ypbind"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure ypbind is removed
package:
name: ypbind
state: absent
tags:
- CCE-84151-0
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- package_ypbind_removed
- unknown_severity
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_ypbind
class remove_ypbind {
package { 'ypbind':
ensure => 'purged',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
package --remove=ypbind
|
Rlogin, Rsh, and Rexec
[ref]groupThe Berkeley r-commands are legacy services which
allow cleartext remote access and have an insecure trust
model. |
contains 2 rules |
Uninstall rsh-server Package
[ref]ruleThe rsh-server package can be removed with the following command:
$ sudo dnf erase rsh-server Rationale:The rsh-server service provides unencrypted remote access service which does not
provide for the confidentiality and integrity of user passwords or the remote session and has very weak
authentication. If a privileged user were to login using this service, the privileged user password
could be compromised. The rsh-server package provides several obsolete and insecure
network services. Removing it decreases the risk of those services' accidental (or intentional)
activation. Identifiers:
CCE-84143-7 References:
BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000095-GPOS-00049 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove rsh-server
# from the system, and may remove any packages
# that depend on rsh-server. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "rsh-server" ; then
dnf remove -y "rsh-server"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure rsh-server is removed
package:
name: rsh-server
state: absent
tags:
- CCE-84143-7
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-IA-5(1)(c)
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_rsh-server_removed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_rsh-server
class remove_rsh-server {
package { 'rsh-server':
ensure => 'purged',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
package --remove=rsh-server
|
Uninstall rsh Package
[ref]rule
The rsh package contains the client commands
for the rsh services Rationale:These legacy clients contain numerous security exposures and have
been replaced with the more secure SSH package. Even if the server is removed,
it is best to ensure the clients are also removed to prevent users from
inadvertently attempting to use these commands and therefore exposing
their credentials. Note that removing the rsh package removes
the clients for rsh ,rcp , and rlogin . Identifiers:
CCE-84142-9 References:
BP28(R1), 3.1.13, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), A.8.2.3, A.13.1.1, A.13.2.1, A.13.2.3, A.14.1.2, A.14.1.3 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove rsh
# from the system, and may remove any packages
# that depend on rsh. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "rsh" ; then
dnf remove -y "rsh"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure rsh is removed
package:
name: rsh
state: absent
tags:
- CCE-84142-9
- NIST-800-171-3.1.13
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- package_rsh_removed
- unknown_severity
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_rsh
class remove_rsh {
package { 'rsh':
ensure => 'purged',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
package --remove=rsh
|
Chat/Messaging Services
[ref]groupThe talk software makes it possible for users to send and receive messages
across systems through a terminal session. |
contains 2 rules |
Uninstall talk-server Package
[ref]ruleThe talk-server package can be removed with the following command: $ sudo dnf erase talk-server Rationale:The talk software presents a security risk as it uses unencrypted protocols
for communications. Removing the talk-server package decreases the
risk of the accidental (or intentional) activation of talk services. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove talk-server
# from the system, and may remove any packages
# that depend on talk-server. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "talk-server" ; then
dnf remove -y "talk-server"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure talk-server is removed
package:
name: talk-server
state: absent
tags:
- CCE-84158-5
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_talk-server_removed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_talk-server
class remove_talk-server {
package { 'talk-server':
ensure => 'purged',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
package --remove=talk-server
|
Uninstall talk Package
[ref]ruleThe talk package contains the client program for the
Internet talk protocol, which allows the user to chat with other users on
different systems. Talk is a communication program which copies lines from one
terminal to the terminal of another user.
The talk package can be removed with the following command:
$ sudo dnf erase talk Rationale:The talk software presents a security risk as it uses unencrypted protocols
for communications. Removing the talk package decreases the
risk of the accidental (or intentional) activation of talk client program. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove talk
# from the system, and may remove any packages
# that depend on talk. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "talk" ; then
dnf remove -y "talk"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure talk is removed
package:
name: talk
state: absent
tags:
- CCE-84157-7
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_talk_removed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_talk
class remove_talk {
package { 'talk':
ensure => 'purged',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
package --remove=talk
|
Telnet
[ref]groupThe telnet protocol does not provide confidentiality or integrity
for information transmitted on the network. This includes authentication
information such as passwords. Organizations which use telnet should be
actively working to migrate to a more secure protocol. |
contains 3 rules |
Uninstall telnet-server Package
[ref]ruleThe telnet-server package can be removed with the following command:
$ sudo dnf erase telnet-server Rationale:It is detrimental for operating systems to provide, or install by default,
functionality exceeding requirements or mission objectives. These
unnecessary capabilities are often overlooked and therefore may remain
unsecure. They increase the risk to the platform by providing additional
attack vectors.
The telnet service provides an unencrypted remote access service which does
not provide for the confidentiality and integrity of user passwords or the
remote session. If a privileged user were to login using this service, the
privileged user password could be compromised.
Removing the telnet-server package decreases the risk of the
telnet service's accidental (or intentional) activation. Identifiers:
CCE-84149-4 References:
BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000095-GPOS-00049 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove telnet-server
# from the system, and may remove any packages
# that depend on telnet-server. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "telnet-server" ; then
dnf remove -y "telnet-server"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure telnet-server is removed
package:
name: telnet-server
state: absent
tags:
- CCE-84149-4
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_telnet-server_removed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_telnet-server
class remove_telnet-server {
package { 'telnet-server':
ensure => 'purged',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
package --remove=telnet-server
|
Remove telnet Clients
[ref]ruleThe telnet client allows users to start connections to other systems via
the telnet protocol. Rationale:The telnet protocol is insecure and unencrypted. The use
of an unencrypted transmission medium could allow an unauthorized user
to steal credentials. The ssh package provides an
encrypted session and stronger security and is included in Red Hat Enterprise Linux 9. Identifiers:
CCE-84146-0 References:
BP28(R1), 3.1.13, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), A.8.2.3, A.13.1.1, A.13.2.1, A.13.2.3, A.14.1.2, A.14.1.3 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove telnet
# from the system, and may remove any packages
# that depend on telnet. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "telnet" ; then
dnf remove -y "telnet"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure telnet is removed
package:
name: telnet
state: absent
tags:
- CCE-84146-0
- NIST-800-171-3.1.13
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_telnet_removed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_telnet
class remove_telnet {
package { 'telnet':
ensure => 'purged',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
package --remove=telnet
|
Disable telnet Service
[ref]ruleThe telnet service configuration file /etc/xinetd.d/telnet
is not created automatically. If it was created manually, check the
/etc/xinetd.d/telnet file and ensure that disable = no
is changed to read disable = yes as follows below:
# description: The telnet server serves telnet sessions; it uses \\
# unencrypted username/password pairs for authentication.
service telnet
{
flags = REUSE
socket_type = stream
wait = no
user = root
server = /usr/sbin/in.telnetd
log_on_failure += USERID
disable = yes
}
If the /etc/xinetd.d/telnet file does not exist, make sure that
the activation of the telnet service on system boot is disabled
via the following command:
The rexec socket can be disabled with the following command:
$ sudo systemctl mask --now rexec.socket Rationale:The telnet protocol uses unencrypted network communication, which
means that data from the login session, including passwords and
all other information transmitted during the session, can be
stolen by eavesdroppers on the network. The telnet protocol is also
subject to man-in-the-middle attacks. Identifiers:
CCE-84150-2 References:
1, 11, 12, 14, 15, 16, 3, 5, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.13, 3.4.7, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-3, PR.PT-4 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'telnet.service'
"$SYSTEMCTL_EXEC" disable 'telnet.service'
"$SYSTEMCTL_EXEC" mask 'telnet.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^telnet.socket'; then
"$SYSTEMCTL_EXEC" stop 'telnet.socket'
"$SYSTEMCTL_EXEC" mask 'telnet.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'telnet.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Disable service telnet
block:
- name: Disable service telnet
systemd:
name: telnet.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84150-2
- NIST-800-171-3.1.13
- NIST-800-171-3.4.7
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-IA-5(1)(c)
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- service_telnet_disabled
- name: Unit Socket Exists - telnet.socket
command: systemctl list-unit-files telnet.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84150-2
- NIST-800-171-3.1.13
- NIST-800-171-3.4.7
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-IA-5(1)(c)
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- service_telnet_disabled
- name: Disable socket telnet
systemd:
name: telnet.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"telnet.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-84150-2
- NIST-800-171-3.1.13
- NIST-800-171-3.4.7
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-IA-5(1)(c)
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- service_telnet_disabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include disable_telnet
class disable_telnet {
service {'telnet':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: telnet.service
enabled: false
mask: true
- name: telnet.socket
enabled: false
mask: true
Remediation script: (show)
[customizations.services]
disabled = ["telnet"]
|
Proxy Server
[ref]groupA proxy server is a very desirable target for a
potential adversary because much (or all) sensitive data for a
given infrastructure may flow through it. Therefore, if one is
required, the system acting as a proxy server should be dedicated
to that purpose alone and be stored in a physically secure
location. The system's default proxy server software is Squid, and
provided in an RPM package of the same name. |
contains 2 rules |
Disable Squid if Possible
[ref]groupIf Squid was installed and activated, but the system
does not need to act as a proxy server, then it should be disabled
and removed. |
contains 2 rules |
Uninstall squid Package
[ref]ruleThe squid package can be removed with the following command: $ sudo dnf erase squid Rationale:If there is no need to make the proxy server software available,
removing it provides a safeguard against its activation. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove squid
# from the system, and may remove any packages
# that depend on squid. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "squid" ; then
dnf remove -y "squid"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure squid is removed
package:
name: squid
state: absent
tags:
- CCE-84238-5
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- package_squid_removed
- unknown_severity
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_squid
class remove_squid {
package { 'squid':
ensure => 'purged',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
package --remove=squid
|
Disable Squid
[ref]rule
The squid service can be disabled with the following command:
$ sudo systemctl mask --now squid.service Rationale:Running proxy server software provides a network-based avenue
of attack, and should be removed if not needed. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'squid.service'
"$SYSTEMCTL_EXEC" disable 'squid.service'
"$SYSTEMCTL_EXEC" mask 'squid.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^squid.socket'; then
"$SYSTEMCTL_EXEC" stop 'squid.socket'
"$SYSTEMCTL_EXEC" mask 'squid.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'squid.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Disable service squid
block:
- name: Disable service squid
systemd:
name: squid.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84239-3
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_squid_disabled
- unknown_severity
- name: Unit Socket Exists - squid.socket
command: systemctl list-unit-files squid.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84239-3
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_squid_disabled
- unknown_severity
- name: Disable socket squid
systemd:
name: squid.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"squid.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-84239-3
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- service_squid_disabled
- unknown_severity
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include disable_squid
class disable_squid {
service {'squid':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: squid.service
enabled: false
mask: true
- name: squid.socket
enabled: false
mask: true
Remediation script: (show)
[customizations.services]
disabled = ["squid"]
|
Network Routing
[ref]groupA router is a very desirable target for a
potential adversary because they fulfill a variety of
infrastructure networking roles such as access to network segments,
gateways to other networks, filtering, etc. Therefore, if one is
required, the system acting as a router should be dedicated
to that purpose alone and be stored in a physically secure
location. The system's default routing software is Quagga, and
provided in an RPM package of the same name. |
contains 1 rule |
Disable Quagga if Possible
[ref]groupIf Quagga was installed and activated, but the system
does not need to act as a router, then it should be disabled
and removed. |
contains 1 rule |
Uninstall quagga Package
[ref]ruleThe quagga package can be removed with the following command: $ sudo dnf erase quagga Rationale:Routing software is typically used on routers to exchange network topology information
with other routers. If routing software is used when not required, system network
information may be unnecessarily transmitted across the network.
If there is no need to make the router software available,
removing it provides a safeguard against its activation. Identifiers:
CCE-84191-6 References:
12, 15, 8, APO13.01, DSS05.02, CCI-000366, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.13.1.1, A.13.2.1, A.14.1.3, CM-7(a), CM-7(b), CM-6(a), PR.PT-4, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove quagga
# from the system, and may remove any packages
# that depend on quagga. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "quagga" ; then
dnf remove -y "quagga"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure quagga is removed
package:
name: quagga
state: absent
tags:
- CCE-84191-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_quagga_removed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_quagga
class remove_quagga {
package { 'quagga':
ensure => 'purged',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
package --remove=quagga
|
SNMP Server
[ref]groupThe Simple Network Management Protocol allows
administrators to monitor the state of network devices, including
computers. Older versions of SNMP were well-known for weak
security, such as plaintext transmission of the community string
(used for authentication) and usage of easily-guessable
choices for the community string. |
contains 2 rules |
Disable SNMP Server if Possible
[ref]groupThe system includes an SNMP daemon that allows for its remote
monitoring, though it not installed by default. If it was installed and
activated but is not needed, the software should be disabled and removed. |
contains 1 rule |
Disable snmpd Service
[ref]rule
The snmpd service can be disabled with the following command:
$ sudo systemctl mask --now snmpd.service Rationale:Running SNMP software provides a network-based avenue of attack, and
should be disabled if not needed. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'snmpd.service'
"$SYSTEMCTL_EXEC" disable 'snmpd.service'
"$SYSTEMCTL_EXEC" mask 'snmpd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^snmpd.socket'; then
"$SYSTEMCTL_EXEC" stop 'snmpd.socket'
"$SYSTEMCTL_EXEC" mask 'snmpd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'snmpd.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Disable service snmpd
block:
- name: Disable service snmpd
systemd:
name: snmpd.service
enabled: 'no'
state: stopped
masked: 'yes'
ignore_errors: 'yes'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90832-7
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_snmpd_disabled
- name: Unit Socket Exists - snmpd.socket
command: systemctl list-unit-files snmpd.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90832-7
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_snmpd_disabled
- name: Disable socket snmpd
systemd:
name: snmpd.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"snmpd.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-90832-7
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_snmpd_disabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include disable_snmpd
class disable_snmpd {
service {'snmpd':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: snmpd.service
enabled: false
mask: true
- name: snmpd.socket
enabled: false
mask: true
Remediation script: (show)
[customizations.services]
disabled = ["snmpd"]
|
Configure SNMP Server if Necessary
[ref]groupIf it is necessary to run the snmpd agent on the system, some best
practices should be followed to minimize the security risk from the
installation. The multiple security models implemented by SNMP cannot be fully
covered here so only the following general configuration advice can be offered:
- use only SNMP version 3 security models and enable the use of authentication and encryption
- write access to the MIB (Management Information Base) should be allowed only if necessary
- all access to the MIB should be restricted following a principle of least privilege
- network access should be limited to the maximum extent possible including restricting to expected network
addresses both in the configuration files and in the system firewall rules
- ensure SNMP agents send traps only to, and accept SNMP queries only from, authorized management
stations
- ensure that permissions on the
snmpd.conf configuration file (by default, in /etc/snmp ) are 640 or more restrictive - ensure that any MIB files' permissions are also 640 or more restrictive
|
contains 1 rule |
Configure SNMP Service to Use Only SNMPv3 or Newer
[ref]ruleEdit /etc/snmp/snmpd.conf , removing any references to rocommunity , rwcommunity , or com2sec .
Upon doing that, restart the SNMP service:
$ sudo service snmpd restart Rationale:Earlier versions of SNMP are considered insecure, as they potentially allow
unauthorized access to detailed system management information. Identifiers:
CCE-87293-7 References:
1311 |
SSH Server
[ref]groupThe SSH protocol is recommended for remote login and
remote file transfer. SSH provides confidentiality and integrity
for data exchanged between two systems, as well as server
authentication, through the use of public key cryptography. The
implementation included with the system is called OpenSSH, and more
detailed documentation is available from its website,
https://www.openssh.com.
Its server program is called sshd and provided by the RPM package
openssh-server . |
contains 18 rules |
Configure OpenSSH Server if Necessary
[ref]groupIf the system needs to act as an SSH server, then
certain changes should be made to the OpenSSH daemon configuration
file /etc/ssh/sshd_config . The following recommendations can be
applied to this file. See the sshd_config(5) man page for more
detailed information. |
contains 17 rules |
Disable Host-Based Authentication
[ref]ruleSSH's cryptographic host-based authentication is
more secure than .rhosts authentication. However, it is
not recommended that hosts unilaterally trust one another, even
within an organization.
The default SSH configuration disables host-based authentication. The appropriate
configuration is used if no value is set for HostbasedAuthentication .
To explicitly disable host-based authentication, add or correct the
following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
HostbasedAuthentication no Rationale:SSH trust relationships mean a compromise on one host
can allow an attacker to move trivially to other hosts. Identifiers:
CCE-90816-0 References:
11, 12, 14, 15, 16, 18, 3, 5, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-3, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.IP-1, PR.PT-3, FIA_UAU.1, SRG-OS-000480-GPOS-00229, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*HostbasedAuthentication\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*HostbasedAuthentication\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*HostbasedAuthentication\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "HostbasedAuthentication no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "HostbasedAuthentication no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable Host-Based Authentication
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "HostbasedAuthentication"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter HostbasedAuthentication is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "HostbasedAuthentication"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "HostbasedAuthentication"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "HostbasedAuthentication"| regex_escape }}\s+
line: HostbasedAuthentication no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90816-0
- CJIS-5.5.6
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-3
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_host_auth
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018%2F04%2F09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D%2Fusr%2Flocal%2Fbin%3A%2Fusr%2Fbin%3A%2Fusr%2Flocal%2Fsbin%3A%2Fusr%2Fsbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20%2Fetc%2Fssh%2Fssh_host_rsa_key%0AHostKey%20%2Fetc%2Fssh%2Fssh_host_ecdsa_key%0AHostKey%20%2Fetc%2Fssh%2Fssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20%2Fetc%2Fsysconfig%2Fsshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh%2Fauthorized_keys%20and%20.ssh%2Fauthorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh%2Fauthorized_keys%0AAuthorizedKeysFile%09.ssh%2Fauthorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20%2Fetc%2Fssh%2Fssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~%2F.ssh%2Fknown_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~%2F.rhosts%20and%20~%2F.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s%2Fkey%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20%2Fetc%2Fpam.d%2Fsshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20%2Fvar%2Frun%2Fsshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20%2Fetc%2Fissue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09%2Fusr%2Flibexec%2Fopenssh%2Fsftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
mode: 0600
path: /etc/ssh/sshd_config
overwrite: true
|
Enable SSH Server firewalld Firewall Exception
[ref]ruleBy default, inbound connections to SSH's port are allowed. If
the SSH server is being used but denied by the firewall, this exception should
be added to the firewall configuration.
To configure firewalld to allow access, run the following command(s):
firewall-cmd --permanent --add-service=ssh Rationale:If inbound SSH connections are expected, adding a firewall rule exception
will allow remote access through the SSH port. |
Allow Only SSH Protocol 2
[ref]ruleOnly SSH protocol version 2 connections should be
permitted. The default setting in
/etc/ssh/sshd_config is correct, and can be
verified by ensuring that the following
line appears:
Protocol 2 Warning:
As of openssh-server version 7.4 and above, the only protocol
supported is version 2, and line Protocol 2 in
/etc/ssh/sshd_config is not necessary. Rationale:SSH protocol version 1 is an insecure implementation of the SSH protocol and
has many well-known vulnerability exploits. Exploits of the SSH daemon could provide
immediate root access to the system. Identifiers:
CCE-90812-9 References:
NT007(R1), 1, 12, 15, 16, 5, 8, 5.5.6, APO13.01, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.13, 3.5.4, CCI-000197, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, 0487, 1449, 1506, A.11.2.6, A.13.1.1, A.13.2.1, A.14.1.3, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1, CM-6(a), AC-17(a), AC-17(2), IA-5(1)(c), SC-13, MA-4(6), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.PT-4, SRG-OS-000074-GPOS-00042, SRG-OS-000480-GPOS-00227, SRG-OS-000033-VMM-000140 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/ssh/sshd_config"; then
sed_command+=('--follow-symlinks')
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^Protocol")
# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "2"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^Protocol\\>" "/etc/ssh/sshd_config"; then
"${sed_command[@]}" "s/^Protocol\\>.*/$formatted_output/gi" "/etc/ssh/sshd_config"
else
# \n is precaution for case where file ends without trailing newline
cce="CCE-90812-9"
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/ssh/sshd_config" >> "/etc/ssh/sshd_config"
printf '%s\n' "$formatted_output" >> "/etc/ssh/sshd_config"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Allow Only SSH Protocol 2
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*Protocol\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*Protocol\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*Protocol\s+
line: Protocol 2
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90812-9
- CJIS-5.5.6
- NIST-800-171-3.1.13
- NIST-800-171-3.5.4
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-13
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- sshd_allow_only_protocol2
|
Disable SSH Access via Empty Passwords
[ref]ruleDisallow SSH login with empty passwords.
The default SSH configuration disables logins with empty passwords. The appropriate
configuration is used if no value is set for PermitEmptyPasswords .
To explicitly disallow SSH login from accounts with empty passwords,
add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
PermitEmptyPasswords no
Any accounts with empty passwords should be disabled immediately, and PAM configuration
should prevent users from being able to assign themselves empty passwords.Rationale:Configuring this setting for the SSH daemon provides additional assurance
that remote login via SSH will require a password, even in the event of
misconfiguration elsewhere. Identifiers:
CCE-90799-8 References:
NT007(R17), 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, 5.5.6, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, 3.1.1, 3.1.5, CCI-000366, CCI-000766, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, FIA_UAU.1, SRG-OS-000106-GPOS-00053, SRG-OS-000480-GPOS-00229, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*PermitEmptyPasswords\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*PermitEmptyPasswords\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*PermitEmptyPasswords\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PermitEmptyPasswords no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "PermitEmptyPasswords no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable SSH Access via Empty Passwords
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "PermitEmptyPasswords"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter PermitEmptyPasswords is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "PermitEmptyPasswords"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "PermitEmptyPasswords"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "PermitEmptyPasswords"| regex_escape }}\s+
line: PermitEmptyPasswords no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90799-8
- CJIS-5.5.6
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- sshd_disable_empty_passwords
|
Disable GSSAPI Authentication
[ref]ruleUnless needed, SSH should not permit extraneous or unnecessary
authentication mechanisms like GSSAPI.
The default SSH configuration disallows authentications based on GSSAPI. The appropriate
configuration is used if no value is set for GSSAPIAuthentication .
To explicitly disable GSSAPI authentication, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
GSSAPIAuthentication no Rationale:GSSAPI authentication is used to provide additional authentication mechanisms to
applications. Allowing GSSAPI authentication through SSH exposes the system's
GSSAPI to remote hosts, increasing the attack surface of the system. Identifiers:
CCE-90808-7 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000318, CCI-000368, CCI-001812, CCI-001813, CCI-001814, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, 0418, 1055, 1402, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-7(a), CM-7(b), CM-6(a), AC-17(a), PR.IP-1, FTP_ITC_EXT.1, SRG-OS-000364-GPOS-00151, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*GSSAPIAuthentication\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*GSSAPIAuthentication\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*GSSAPIAuthentication\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "GSSAPIAuthentication no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "GSSAPIAuthentication no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable GSSAPI Authentication
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "GSSAPIAuthentication"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter GSSAPIAuthentication is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "GSSAPIAuthentication"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "GSSAPIAuthentication"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "GSSAPIAuthentication"| regex_escape }}\s+
line: GSSAPIAuthentication no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90808-7
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_gssapi_auth
|
Disable Kerberos Authentication
[ref]ruleUnless needed, SSH should not permit extraneous or unnecessary
authentication mechanisms like Kerberos.
The default SSH configuration disallows authentication validation through Kerberos.
The appropriate configuration is used if no value is set for KerberosAuthentication .
To explicitly disable Kerberos authentication, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
KerberosAuthentication no Rationale:Kerberos authentication for SSH is often implemented using GSSAPI. If Kerberos
is enabled through SSH, the SSH daemon provides a means of access to the
system's Kerberos implementation. Vulnerabilities in the system's Kerberos
implementations may be subject to exploitation. Identifiers:
CCE-90802-0 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000318, CCI-000368, CCI-001812, CCI-001813, CCI-001814, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, FTP_ITC_EXT.1, SRG-OS-000364-GPOS-00151, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*KerberosAuthentication\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*KerberosAuthentication\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*KerberosAuthentication\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "KerberosAuthentication no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "KerberosAuthentication no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable Kerberos Authentication
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "KerberosAuthentication"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter KerberosAuthentication is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "KerberosAuthentication"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "KerberosAuthentication"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "KerberosAuthentication"| regex_escape }}\s+
line: KerberosAuthentication no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90802-0
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_kerb_auth
|
Disable SSH Support for .rhosts Files
[ref]ruleSSH can emulate the behavior of the obsolete rsh
command in allowing users to enable insecure access to their
accounts via .rhosts files.
The default SSH configuration disables support for .rhosts . The appropriate
configuration is used if no value is set for IgnoreRhosts .
To explicitly disable support for .rhosts files, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
IgnoreRhosts yes Rationale:SSH trust relationships mean a compromise on one host
can allow an attacker to move trivially to other hosts. Identifiers:
CCE-90797-2 References:
11, 12, 14, 15, 16, 18, 3, 5, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.12, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.IP-1, PR.PT-3, FIA_UAU.1, SRG-OS-000480-GPOS-00227, SRG-OS-000107-VMM-000530 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*IgnoreRhosts\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*IgnoreRhosts\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*IgnoreRhosts\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "IgnoreRhosts yes" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "IgnoreRhosts yes" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable SSH Support for .rhosts Files
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "IgnoreRhosts"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter IgnoreRhosts is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "IgnoreRhosts"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "IgnoreRhosts"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "IgnoreRhosts"| regex_escape }}\s+
line: IgnoreRhosts yes
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90797-2
- CJIS-5.5.6
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_rhosts
|
Disable SSH Root Login
[ref]ruleThe root user should never be allowed to login to a
system directly over a network.
To disable root login via SSH, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
PermitRootLogin no Rationale:Even though the communications channel may be encrypted, an additional layer of
security is gained by extending the policy of not logging directly on as root.
In addition, logging in with a user-specific account provides individual
accountability of actions performed on the system and also helps to minimize
direct attack attempts on root's password. Identifiers:
CCE-90800-4 References:
BP28(R19), NT007(R21), 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.6, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.1.5, CCI-000366, CCI-000770, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-6(2), AC-17(a), IA-2, IA-2(5), CM-7(a), CM-7(b), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, FIA_UAU.1, SRG-OS-000109-GPOS-00056, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*PermitRootLogin\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*PermitRootLogin\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*PermitRootLogin\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PermitRootLogin no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "PermitRootLogin no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable SSH Root Login
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "PermitRootLogin"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter PermitRootLogin is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "PermitRootLogin"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "PermitRootLogin"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "PermitRootLogin"| regex_escape }}\s+
line: PermitRootLogin no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90800-4
- CJIS-5.5.6
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(2)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-IA-2
- NIST-800-53-IA-2(5)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_root_login
|
Disable SSH Support for User Known Hosts
[ref]ruleSSH can allow system users to connect to systems if a cache of the remote
systems public keys is available. This should be disabled.
To ensure this behavior is disabled, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
IgnoreUserKnownHosts yes Rationale:Configuring this setting for the SSH daemon provides additional
assurance that remote login via SSH will require a password, even
in the event of misconfiguration elsewhere. Identifiers:
CCE-90796-4 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, FIA_UAU.1, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*IgnoreUserKnownHosts\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*IgnoreUserKnownHosts\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*IgnoreUserKnownHosts\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "IgnoreUserKnownHosts yes" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "IgnoreUserKnownHosts yes" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable SSH Support for User Known Hosts
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "IgnoreUserKnownHosts"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter IgnoreUserKnownHosts is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "IgnoreUserKnownHosts"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "IgnoreUserKnownHosts"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "IgnoreUserKnownHosts"| regex_escape }}\s+
line: IgnoreUserKnownHosts yes
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90796-4
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_user_known_hosts
|
Disable X11 Forwarding
[ref]ruleThe X11Forwarding parameter provides the ability to tunnel X11 traffic
through the connection to enable remote graphic connections.
SSH has the capability to encrypt remote X11 connections when SSH's
X11Forwarding option is enabled.
The default SSH configuration disables X11Forwarding. The appropriate
configuration is used if no value is set for X11Forwarding .
To explicitly disable X11 Forwarding, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
X11Forwarding no Rationale:Disable X11 forwarding unless there is an operational requirement to use X11
applications directly. There is a small risk that the remote X11 servers of
users who are logged in via SSH with X11 forwarding could be compromised by
other users on the X11 server. Note that even if X11 forwarding is disabled,
users can always install their own forwarders. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*X11Forwarding\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*X11Forwarding\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*X11Forwarding\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "X11Forwarding no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "X11Forwarding no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable X11 Forwarding
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "X11Forwarding"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter X11Forwarding is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "X11Forwarding"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "X11Forwarding"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "X11Forwarding"| regex_escape }}\s+
line: X11Forwarding no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90798-0
- NIST-800-53-CM-6(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_x11_forwarding
|
Do Not Allow SSH Environment Options
[ref]ruleEnsure that users are not able to override environment variables of the SSH daemon.
The default SSH configuration disables environment processing. The appropriate
configuration is used if no value is set for PermitUserEnvironment .
To explicitly disable Environment options, add or correct the following
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
PermitUserEnvironment no Rationale:SSH environment options potentially allow users to bypass
access restriction in some configurations. Identifiers:
CCE-90803-8 References:
11, 3, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, SRG-OS-000480-GPOS-00229, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*PermitUserEnvironment\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*PermitUserEnvironment\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*PermitUserEnvironment\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PermitUserEnvironment no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "PermitUserEnvironment no" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Do Not Allow SSH Environment Options
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "PermitUserEnvironment"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter PermitUserEnvironment is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "PermitUserEnvironment"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "PermitUserEnvironment"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "PermitUserEnvironment"| regex_escape }}\s+
line: PermitUserEnvironment no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90803-8
- CJIS-5.5.6
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_do_not_permit_user_env
|
Enable Use of Strict Mode Checking
[ref]ruleSSHs StrictModes option checks file and ownership permissions in
the user's home directory .ssh folder before accepting login. If world-
writable permissions are found, logon is rejected.
The default SSH configuration has StrictModes enabled. The appropriate
configuration is used if no value is set for StrictModes .
To explicitly enable StrictModes in SSH, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
StrictModes yes Rationale:If other users have access to modify user-specific SSH configuration files, they
may be able to log into the system as another user. Identifiers:
CCE-90809-5 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6, AC-17(a), CM-6(a), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*StrictModes\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*StrictModes\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*StrictModes\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "StrictModes yes" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "StrictModes yes" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Enable Use of Strict Mode Checking
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "StrictModes"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter StrictModes is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "StrictModes"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "StrictModes"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "StrictModes"| regex_escape }}\s+
line: StrictModes yes
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90809-5
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_enable_strictmodes
|
Enable SSH Warning Banner
[ref]ruleTo enable the warning banner and ensure it is consistent
across the system, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
Banner /etc/issue
Another section contains information on how to create an
appropriate system-wide warning banner.Rationale:The warning message reinforces policy awareness during the logon process and
facilitates possible legal action against attackers. Alternatively, systems
whose ownership should not be obvious should ensure usage of a banner that does
not provide easy attribution. Identifiers:
CCE-90807-9 References:
1, 12, 15, 16, 5.5.6, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-000050, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(c), AC-17(a), CM-6(a), PR.AC-7, FTA_TAB.1, SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007, SRG-OS-000228-GPOS-00088, SRG-OS-000023-VMM-000060, SRG-OS-000024-VMM-000070 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*Banner\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*Banner\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*Banner\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "Banner /etc/issue" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "Banner /etc/issue" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Enable SSH Warning Banner
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "Banner"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter Banner is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "Banner"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "Banner"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "Banner"| regex_escape }}\s+
line: Banner /etc/issue
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90807-9
- CJIS-5.5.6
- NIST-800-171-3.1.9
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_enable_warning_banner
|
Enable SSH Print Last Log
[ref]ruleEnsure that SSH will display the date and time of the last successful account logon.
The default SSH configuration enables print of the date and time of the last login.
The appropriate configuration is used if no value is set for PrintLastLog .
To explicitly enable LastLog in SSH, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
PrintLastLog yes Rationale:Providing users feedback on when account accesses last occurred facilitates user
recognition and reporting of unauthorized account use. Identifiers:
CCE-90804-6 References:
1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, CCI-000366, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-9, AC-17(a), CM-6(a), PR.AC-7, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*PrintLastLog\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*PrintLastLog\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*PrintLastLog\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PrintLastLog yes" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "PrintLastLog yes" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Enable SSH Print Last Log
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "PrintLastLog"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter PrintLastLog is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "PrintLastLog"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "PrintLastLog"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "PrintLastLog"| regex_escape }}\s+
line: PrintLastLog yes
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90804-6
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-9
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_print_last_log
|
Set LogLevel to INFO
[ref]ruleThe INFO parameter specifices that record login and logout activity will be logged.
The default SSH configuration sets the log level to INFO. The appropriate
configuration is used if no value is set for LogLevel .
To explicitly specify the log level in SSH, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf :
LogLevel INFO Rationale:SSH provides several logging levels with varying amounts of verbosity. DEBUG is specifically
not recommended other than strictly for debugging SSH communications since it provides
so much data that it is difficult to identify important security information. INFO level is the
basic level that only records login activity of SSH users. In many situations, such as Incident
Response, it is important to determine when a particular user was active on a system. The
logout record can eliminate those users who disconnected, which helps narrow the field. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
mkdir -p /etc/ssh/sshd_config.d
touch /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
LC_ALL=C sed -i "/^\s*LogLevel\s\+/Id" "/etc/ssh/sshd_config"
LC_ALL=C sed -i "/^\s*LogLevel\s\+/Id" "/etc/ssh/sshd_config.d"/*.conf
if [ -e "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" ] ; then
LC_ALL=C sed -i "/^\s*LogLevel\s\+/Id" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
touch "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
cp "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "LogLevel INFO" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" > "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
printf '%s\n' "LogLevel INFO" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak" >> "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Set LogLevel to INFO
block:
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: ^\s*{{ "LogLevel"| regex_escape }}\s+
state: absent
- name: Check if /etc/ssh/sshd_config.d exists
stat:
path: /etc/ssh/sshd_config.d
register: _etc_ssh_sshd_config_d_exists
- name: Check if the parameter LogLevel is present in /etc/ssh/sshd_config.d
find:
paths: /etc/ssh/sshd_config.d
recurse: 'yes'
follow: 'no'
contains: ^\s*{{ "LogLevel"| regex_escape }}\s+
register: _etc_ssh_sshd_config_d_has_parameter
when: _etc_ssh_sshd_config_d_exists.stat.isdir is defined and _etc_ssh_sshd_config_d_exists.stat.isdir
- name: Remove parameter from files in /etc/ssh/sshd_config.d
lineinfile:
path: '{{ item.path }}'
create: false
regexp: ^\s*{{ "LogLevel"| regex_escape }}\s+
state: absent
with_items: '{{ _etc_ssh_sshd_config_d_has_parameter.files }}'
when: _etc_ssh_sshd_config_d_has_parameter.matched
- name: Insert correct line to /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
lineinfile:
path: /etc/ssh/sshd_config.d/00-complianceascode-hardening.conf
create: true
regexp: ^\s*{{ "LogLevel"| regex_escape }}\s+
line: LogLevel INFO
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90813-7
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_loglevel_info
|
Set SSH authentication attempt limit
[ref]ruleThe MaxAuthTries parameter specifies the maximum number of authentication attempts
permitted per connection. Once the number of failures reaches half this value, additional failures are logged.
to set MaxAUthTries edit /etc/ssh/sshd_config as follows:
MaxAuthTries 5 Rationale:Setting the MaxAuthTries parameter to a low number will minimize the risk of successful
brute force attacks to the SSH server. Identifiers:
CCE-90810-3 References:
0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sshd_max_auth_tries_value='5'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*MaxAuthTries\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "MaxAuthTries $sshd_max_auth_tries_value" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "MaxAuthTries $sshd_max_auth_tries_value" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value sshd_max_auth_tries_value # promote to variable
set_fact:
sshd_max_auth_tries_value: !!str 5
tags:
- always
- name: Set SSH authentication attempt limit
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*MaxAuthTries\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*MaxAuthTries\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxAuthTries\s+
line: MaxAuthTries {{ sshd_max_auth_tries_value }}
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90810-3
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_max_auth_tries
|
Distribute the SSH Server configuration to multiple files in a config directory.
[ref]ruleMake sure to have the Include /etc/ssh/sshd_config.d/*.conf line in the /etc/ssh/sshd_config file.
Ideally, don't have any active configuration directives in that file, and distribute the service configuration
to several files in the /etc/ssh/sshd_config.d directory. Rationale:This form of distributed configuration is considered as a good practice, and as other sshd rules assume that directives in files in the /etc/ssh/sshd_config.d config directory are effective, there has to be a rule that ensures this.
Aside from that, having multiple configuration files makes the SSH Server configuration changes easier to partition according to the reason that they were introduced, and therefore it should help to perform merges of hardening updates. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if test -f /etc/ssh/sshd_config.d/sshd_config_original.conf; then
printf '%s\n' "Remediation probably already happened, '/etc/ssh/sshd_config.d/sshd_config_original.conf' already exists, not doing anything." >&2
false 1
elif grep -Eq '^\s*Include\s+/etc/ssh/sshd_config\.d/\*\.conf' /etc/ssh/sshd_config && ! grep -Eq '^\s*Match\s' /etc/ssh/sshd_config; then
printf '%s\n' "Remediation probably already happened, '/etc/ssh/sshd_config' already contains the include directive." >&2
false 1
else
mkdir -p /etc/ssh/sshd_config.d
mv /etc/ssh/sshd_config /etc/ssh/sshd_config.d/sshd_config_original.conf
cat > /etc/ssh/sshd_config << EOF
# To modify the system-wide sshd configuration, create a *.conf file under
# /etc/ssh/sshd_config.d/ which will be automatically included below
Include /etc/ssh/sshd_config.d/*.conf
EOF
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on SSH Server Private *_key Key Files
[ref]rule
To properly set the permissions of /etc/ssh/*_key , run the command:
$ sudo chmod 0600 /etc/ssh/*_key Rationale:If an unauthorized user obtains the private SSH host key file, the host could be
impersonated. Identifiers:
CCE-90820-2 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.13, 3.13.10, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/ssh/ -maxdepth 1 -perm /u+xs,g+xwrs,o+xwrt -type f -regex '^.*_key$' -exec chmod u-xs,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Find /etc/ssh/ file(s)
command: find -H /etc/ssh/ -maxdepth 1 -perm /u+xs,g+xwrs,o+xwrt -type f -regex
"^.*_key$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90820-2
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_sshd_private_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /etc/ssh/ file(s)
file:
path: '{{ item }}'
mode: u-xs,g-xwrs,o-xwrt
state: file
with_items:
- '{{ files_found.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-90820-2
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_sshd_private_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Puppet snippet: (show)
include ssh_private_key_perms
class ssh_private_key_perms {
exec { 'sshd_priv_key':
command => "chmod 0640 /etc/ssh/*_key",
path => '/bin:/usr/bin'
}
}
|
USBGuard daemon
[ref]groupThe USBGuard daemon enforces the USB device authorization policy for all USB devices. |
contains 3 rules |
Install usbguard Package
[ref]rule
The usbguard package can be installed with the following command:
$ sudo dnf install usbguard Rationale:usbguard is a software framework that helps to protect
against rogue USB devices by implementing basic whitelisting/blacklisting
capabilities based on USB device attributes. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if ! grep -q s390x /proc/sys/kernel/osrelease; then
if ! rpm -q --quiet "usbguard" ; then
dnf install -y "usbguard"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure usbguard is installed
package:
name: usbguard
state: present
tags:
- CCE-84203-9
- NIST-800-53-CM-8(3)
- NIST-800-53-IA-3
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_usbguard_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_usbguard
class install_usbguard {
package { 'usbguard':
ensure => 'installed',
}
}
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
package --add=usbguard
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
config:
ignition:
version: 3.1.0
extensions:
- usbguard
Remediation script: (show)
[[packages]]
name = "usbguard"
version = "*"
|
Enable the USBGuard Service
[ref]ruleThe USBGuard service should be enabled.
The usbguard service can be enabled with the following command:
$ sudo systemctl enable usbguard.service Rationale:The usbguard service must be running in order to
enforce the USB device authorization policy for all USB devices. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if ! grep -q s390x /proc/sys/kernel/osrelease && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'usbguard.service'
"$SYSTEMCTL_EXEC" start 'usbguard.service'
"$SYSTEMCTL_EXEC" enable 'usbguard.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Enable service usbguard
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service usbguard
service:
name: usbguard
enabled: 'yes'
state: started
masked: 'no'
when:
- '"usbguard" in ansible_facts.packages'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-84205-4
- NIST-800-53-CM-8(3)(a)
- NIST-800-53-IA-3
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_usbguard_enabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include enable_usbguard
class enable_usbguard {
service {'usbguard':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
annotations:
complianceascode.io/depends-on: xccdf_org.ssgproject.content_rule_package_usbguard_installed
spec:
config:
ignition:
version: 3.1.0
systemd:
units:
- name: usbguard.service
enabled: true
Remediation script: (show)
[customizations.services]
enabled = ["usbguard"]
|
Authorize Human Interface Devices and USB hubs in USBGuard daemon
[ref]ruleTo allow authorization of USB devices combining human interface device and hub capabilities
by USBGuard daemon,
add the line
allow with-interface match-all { 03:*:* 09:00:* }
to /etc/usbguard/rules.conf . Warning:
This rule should be understood primarily as a convenience administration feature. This rule ensures that if the USBGuard default rules.conf file is present, it will alter it so that USB human interface devices and hubs are allowed. However, if the rules.conf file is altered by system administrator, the rule does not check if USB human interface devices and hubs are allowed. This assumes that an administrator modified the file with some purpose in mind. Rationale:Without allowing Human Interface Devices, it might not be possible
to interact with the system. Without allowing hubs, it might not be possible to use any
USB devices on the system. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ! grep -q s390x /proc/sys/kernel/osrelease; then
echo "allow with-interface match-all { 03:*:* 09:00:* }" >> /etc/usbguard/rules.conf
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation script: (show)
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
annotations:
complianceascode.io/depends-on: xccdf_org.ssgproject.content_rule_package_usbguard_installed
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:,{{ %0Aallow%20with-interface%20match-all%20%7B%2003%3A%2A%3A%2A%2009%3A00%3A%2A%20%7D }}
mode: 0600
path: /etc/usbguard/rules.d/75-hid-and-hub.conf
overwrite: true
|