contains 158 rules |
System Settings
[ref]groupContains rules that check correct system settings. |
contains 139 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 27 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 2 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 2 rules |
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 2 rules |
Install AIDE
[ref]ruleThe aide package can be installed with the following command:
$ sudo yum install aide Rationale:The AIDE package must be installed if it is to be available for integrity checking. 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, 11.5.2, SRG-OS-000445-GPOS-00199, OL07-00-020029, SV-251701r880693_rule Remediation script: (show)
[[packages]]
name = "aide"
version = "*"
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
package --add=aide
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_aide
class install_aide {
package { 'aide':
ensure => 'installed',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "aide" ; then
yum install -y "aide"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure aide is installed
package:
name: aide
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.3
- DISA-STIG-OL07-00-020029
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_aide_installed
|
Build and Test AIDE Database
[ref]ruleRun the following command to generate a new database:
$ sudo /usr/sbin/aide --init
By default, the database will be written to the file
/var/lib/aide/aide.db.new.gz .
Storing the database, the configuration file /etc/aide.conf , and the binary
/usr/sbin/aide
(or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity.
The newly-generated database can be installed as follows:
$ sudo cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz
To initiate a manual check, run the following command:
$ sudo /usr/sbin/aide --check
If this check produces any unexpected output, investigate.Rationale:For AIDE to be effective, an initial database of "known-good" information about files
must be captured and it should be able to be verified against the installed files. 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, 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, 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, 11.5.2, SRG-OS-000445-GPOS-00199, OL07-00-020029, SV-251701r880693_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "aide" ; then
yum install -y "aide"
fi
/usr/sbin/aide --init
/bin/cp -p /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Ensure AIDE is installed
package:
name: '{{ item }}'
state: present
with_items:
- aide
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.3
- DISA-STIG-OL07-00-020029
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_build_database
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Build and Test AIDE Database
command: /usr/sbin/aide --init
changed_when: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.3
- DISA-STIG-OL07-00-020029
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_build_database
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check whether the stock AIDE Database exists
stat:
path: /var/lib/aide/aide.db.new.gz
register: aide_database_stat
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.3
- DISA-STIG-OL07-00-020029
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_build_database
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Stage AIDE Database
copy:
src: /var/lib/aide/aide.db.new.gz
dest: /var/lib/aide/aide.db.gz
backup: true
remote_src: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (aide_database_stat.stat.exists is defined and aide_database_stat.stat.exists)
tags:
- CJIS-5.10.1.3
- DISA-STIG-OL07-00-020029
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_build_database
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Disk Partitioning
[ref]groupTo ensure separation and protection of data, there
are top-level system directories which should be placed on their
own physical partition or logical volume. The installer's default
partitioning scheme creates separate logical volumes for
/ , /boot , and swap .
- If starting with any of the default layouts, check the box to
\"Review and modify partitioning.\" This allows for the easy creation
of additional logical volumes inside the volume group already
created, though it may require making
/ 's logical volume smaller to
create space. In general, using logical volumes is preferable to
using partitions because they can be more easily adjusted
later. - If creating a custom layout, create the partitions mentioned in
the previous paragraph (which the installer will require anyway),
as well as separate ones described in the following sections.
If a system has already been installed, and the default
partitioning
scheme was used, it is possible but nontrivial to
modify it to create separate logical volumes for the directories
listed above. The Logical Volume Manager (LVM) makes this possible.
See the LVM HOWTO at
http://tldp.org/HOWTO/LVM-HOWTO/
for more detailed information on LVM. |
contains 9 rules |
Ensure /boot Located On Separate Partition
[ref]ruleIt is recommended that the /boot directory resides on a separate
partition. This makes it easier to apply restrictions e.g. through the
noexec mount option. Eventually, the /boot partition can
be configured not to be mounted automatically with the noauto mount
option. Rationale:The /boot partition contains the kernel and bootloader files.
Access to this partition should be restricted. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /boot
|
Ensure /home Located On Separate Partition
[ref]ruleIf user home directories will be stored locally, create a separate partition
for /home at installation time (or migrate it later using LVM). If
/home will be mounted from another system such as an NFS server, then
creating a separate partition is not necessary at installation time, and the
mountpoint can instead be configured later. Rationale:Ensuring that /home is mounted on its own partition enables the
setting of more restrictive mount options, and also helps ensure that
users cannot trivially fill partitions used for log or audit data storage. References:
BP28(R12), 12, 15, 8, APO13.01, DSS05.02, CCI-000366, CCI-001208, 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-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-021310, SV-221754r603803_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /home
|
Ensure /opt Located On Separate Partition
[ref]ruleIt is recommended that the /opt directory resides on a separate
partition. Rationale:The /opt partition contains additional software, usually installed
outside the packaging system. Putting this directory on a separate partition
makes it easier to apply restrictions e.g. through the nosuid mount
option. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /opt
|
Ensure /srv Located On Separate Partition
[ref]ruleIf a file server (FTP, TFTP...) is hosted locally, create a separate partition
for /srv at installation time (or migrate it later using LVM). If
/srv will be mounted from another system such as an NFS server, then
creating a separate partition is not necessary at installation time, and the
mountpoint can instead be configured later. Rationale:Srv deserves files for local network file server such as FTP. Ensuring
that /srv is mounted on its own partition enables the setting of
more restrictive mount options, and also helps ensure that
users cannot trivially fill partitions used for log or audit data storage. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /srv
|
Ensure /tmp Located On Separate Partition
[ref]ruleThe /tmp directory is a world-writable directory used
for temporary file storage. Ensure it has its own partition or
logical volume at installation time, or migrate it using LVM. Rationale:The /tmp partition is used as temporary storage by many programs.
Placing /tmp in its own partition enables the setting of more
restrictive mount options, which can help protect programs which use it. References:
BP28(R12), 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-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-021340, SV-221757r603260_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /tmp
|
Ensure /usr Located On Separate Partition
[ref]ruleIt is recommended that the /usr directory resides on a separate
partition. Rationale:The /usr partition contains system software, utilities and files.
Putting it on a separate partition allows limiting its size and applying
restrictions through mount options. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /usr
|
Ensure /var Located On Separate Partition
[ref]ruleThe /var directory is used by daemons and other system
services to store frequently-changing data. Ensure that /var has its own partition
or logical volume at installation time, or migrate it using LVM. Rationale:Ensuring that /var is mounted on its own partition enables the
setting of more restrictive mount options. This helps protect
system services such as daemons or other programs which use it.
It is not uncommon for the /var directory to contain
world-writable directories installed by other software packages. References:
BP28(R12), 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-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-021320, SV-221755r603260_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var
|
Ensure /var/log Located On Separate Partition
[ref]ruleSystem logs are stored in the /var/log directory.
Ensure that /var/log has its own partition or logical
volume at installation time, or migrate it using LVM. Rationale:Placing /var/log in its own partition
enables better separation between log files
and other files in /var/ . References:
BP28(R12), BP28(R47), 1, 12, 14, 15, 16, 3, 5, 6, 8, APO11.04, APO13.01, BAI03.05, DSS05.02, DSS05.04, DSS05.07, MEA02.01, CCI-000366, 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 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.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, CIP-007-3 R6.5, CM-6(a), AU-4, SC-5(2), PR.PT-1, PR.PT-4, SRG-OS-000480-GPOS-00227 Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/log
|
Ensure /var/tmp Located On Separate Partition
[ref]ruleThe /var/tmp directory is a world-writable directory used
for temporary file storage. Ensure it has its own partition or
logical volume at installation time, or migrate it using LVM. Rationale:The /var/tmp partition is used as temporary storage by many programs.
Placing /var/tmp in its own partition enables the setting of more
restrictive mount options, which can help protect programs which use it. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/tmp
|
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 11 rules |
Install sudo Package
[ref]ruleThe sudo package can be installed with the following command:
$ sudo yum 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 script: (show)
[[packages]]
name = "sudo"
version = "*"
Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
package --add=sudo
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_sudo
class install_sudo {
package { 'sudo':
ensure => 'installed',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! rpm -q --quiet "sudo" ; then
yum install -y "sudo"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure sudo is installed
package:
name: sudo
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-CM-6(a)
- PCI-DSSv4-10.2.1.5
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_sudo_installed
|
Ensure sudo Runs In A Minimal Environment - sudo env_reset
[ref]ruleThe sudo env_reset tag, when specified, will run the command in a minimal environment,
containing the TERM, PATH, HOME, MAIL, SHELL, LOGNAME, USER and SUDO_* variables.
This should be enabled by making sure that the env_reset tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . Rationale:Forcing sudo to reset the environment ensures that environment variables are not passed on to the
command accidentaly, preventing leak of potentially sensitive information. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults[\s]*\benv_reset\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option env_reset
echo "Defaults env_reset" >> /etc/sudoers
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Ensure env_reset is enabled in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults.*\benv_reset\b.*$
line: Defaults env_reset
validate: /usr/sbin/visudo -cf %s
tags:
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_add_env_reset
|
Ensure sudo Ignores Commands In Current Dir - sudo ignore_dot
[ref]ruleThe sudo ignore_dot tag, when specified, will ignore the current directory
in the PATH environment variable.
This should be enabled by making sure that the ignore_dot tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . Rationale:Ignoring the commands in the user's current directory prevents an attacker from executing commands
downloaded locally. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults[\s]*\bignore_dot\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option ignore_dot
echo "Defaults ignore_dot" >> /etc/sudoers
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Ensure ignore_dot is enabled in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults.*\bignore_dot\b.*$
line: Defaults ignore_dot
validate: /usr/sbin/visudo -cf %s
tags:
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_add_ignore_dot
|
Ensure Privileged Escalated Commands Cannot Execute Other Commands - sudo NOEXEC
[ref]ruleThe sudo NOEXEC tag, when specified, prevents user executed
commands from executing other commands, like a shell for example.
This should be enabled by making sure that the NOEXEC tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . Rationale:Restricting the capability of sudo allowed commands to execute sub-commands
prevents users from running programs with privileges they wouldn't have otherwise. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults[\s]*\bnoexec\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option noexec
echo "Defaults noexec" >> /etc/sudoers
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Ensure noexec is enabled in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults.*\bnoexec\b.*$
line: Defaults noexec
validate: /usr/sbin/visudo -cf %s
tags:
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- sudo_add_noexec
|
Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo requiretty
[ref]ruleThe sudo requiretty tag, when specified, will only execute sudo
commands from users logged in to a real tty.
This should be enabled by making sure that the requiretty tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . Rationale:Restricting the use cases in which a user is allowed to execute sudo commands
reduces the attack surface. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults[\s]*\brequiretty\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option requiretty
echo "Defaults requiretty" >> /etc/sudoers
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Ensure requiretty is enabled in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults.*\brequiretty\b.*$
line: Defaults requiretty
validate: /usr/sbin/visudo -cf %s
tags:
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_add_requiretty
|
Ensure sudo umask is appropriate - sudo umask
[ref]ruleThe sudo umask tag, when specified, will be added the to the user's umask in the
command environment.
The umask should be configured by making sure that the umask=0077 tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . Rationale:The umask value influences the permissions assigned to files when they are created.
A misconfigured umask value could result in files with excessive permissions that can be read or
written to by unauthorized users. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
var_sudo_umask='0077'
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults[\s]*\bumask=\w+\b\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option umask
echo "Defaults umask=${var_sudo_umask}" >> /etc/sudoers
else
# sudoers file defines Option umask, remediate if appropriate value is not set
if ! grep -P "^[\s]*Defaults.*\bumask=${var_sudo_umask}\b.*$" /etc/sudoers; then
escaped_variable=${var_sudo_umask//$'/'/$'\/'}
sed -Ei "s/(^[\s]*Defaults.*\bumask=)[-]?.+(\b.*$)/\1$escaped_variable\2/" /etc/sudoers
fi
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sudo_umask # promote to variable
set_fact:
var_sudo_umask: !!str 0077
tags:
- always
- name: Ensure umask is enabled with the appropriate value in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults\s(.*)\bumask=[-]?.+\b(.*)$
line: Defaults \1umask={{ var_sudo_umask }}\2
validate: /usr/sbin/visudo -cf %s
backrefs: true
register: edit_sudoers_umask_option
tags:
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_add_umask
- name: Enable umask option with appropriate value in /etc/sudoers
lineinfile:
path: /etc/sudoers
line: Defaults umask={{ var_sudo_umask }}
validate: /usr/sbin/visudo -cf %s
when: edit_sudoers_umask_option is defined and not edit_sudoers_umask_option.changed
tags:
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_add_umask
|
Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo use_pty
[ref]ruleThe sudo use_pty tag, when specified, will only execute sudo
commands from users logged in to a real tty.
This should be enabled by making sure that the use_pty tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . Rationale:Requiring that sudo commands be run in a pseudo-terminal can prevent an attacker from retaining
access to the user's terminal after the main program has finished executing. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q sudo; then
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults[\s]*\buse_pty\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option use_pty
echo "Defaults use_pty" >> /etc/sudoers
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_add_use_pty
- name: Ensure use_pty is enabled in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults.*\buse_pty\b.*$
line: Defaults use_pty
validate: /usr/sbin/visudo -cf %s
when: '"sudo" in ansible_facts.packages'
tags:
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_add_use_pty
|
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. 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, OL07-00-010350, SV-228569r853731_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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 $f with visudo"
fi
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Find /etc/sudoers.d/ files
find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- DISA-STIG-OL07-00-010350
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_remove_no_authenticate
- name: Remove lines containing !authenticate from sudoers files
replace:
regexp: (^(?!#).*[\s]+\!authenticate.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- DISA-STIG-OL07-00-010350
- 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. 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, OL07-00-010340, SV-221692r860860_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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 $f with visudo"
fi
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Find /etc/sudoers.d/ files
find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- DISA-STIG-OL07-00-010340
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_remove_nopasswd
- name: Remove lines containing NOPASSWD from sudoers files
replace:
regexp: (^(?!#).*[\s]+NOPASSWD[\s]*\:.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- DISA-STIG-OL07-00-010340
- 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
|
Explicit arguments in sudo specifications
[ref]ruleAll commands in the sudoers file must strictly specify the arguments allowed to be used for a given user.
If the command is supposed to be executed only without arguments, pass "" as an argument in the corresponding user specification. Warning:
This rule doesn't come with a remediation, as absence of arguments in the user spec doesn't mean that the command is intended to be executed with no arguments. Warning:
The rule can produce false findings when an argument contains a comma - sudoers syntax allows comma escaping using backslash, but the check doesn't support that. For example, root ALL=(ALL) echo 1\,2 allows root to execute echo 1,2 , but the check would interpret it as two commands echo 1\ and 2 . Rationale:Any argument can modify quite significantly the behavior of a program, whether regarding the
realized operation (read, write, delete, etc.) or accessed resources (path in a file system tree). To
avoid any possibility of misuse of a command by a user, the ambiguities must be removed at the
level of its specification.
For example, on some systems, the kernel messages are only accessible by root.
If a user nevertheless must have the privileges to read them, the argument of the dmesg command has to be restricted
in order to prevent the user from flushing the buffer through the -c option:
user ALL = dmesg ""
|
Don't define allowed commands in sudoers by means of exclusion
[ref]rulePolicies applied by sudo through the sudoers file should not involve negation.
Each user specification in the sudoers file contains a comma-delimited list of command specifications.
The definition can make use glob patterns, as well as of negations.
Indirect definition of those commands by means of exclusion of a set of commands is trivial to bypass, so it is not allowed to use such constructs. Warning:
This rule doesn't come with a remediation, as negations indicate design issues with the sudoers user specifications design. Just removing negations doesn't increase the security - you typically have to rethink the definition of allowed commands to fix the issue. Rationale:Specifying access right using negation is inefficient and can be easily circumvented.
For example, it is expected that a specification like
# To avoid absolutely , this rule can be easily circumvented!
user ALL = ALL ,!/ bin/sh
prevents the execution of the shell
but that’s not the case: just copy the binary /bin/sh to a different name to make it executable
again through the rule keyword ALL . |
Updating Software
[ref]groupThe yum 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.
Oracle Linux 7 systems contain an installed software catalog called
the RPM database, which records metadata of installed packages. Consistently using
yum or the graphical Software Update for all software installation
allows for insight into the current inventory of installed software on the system.
|
contains 5 rules |
Ensure gpgcheck Enabled In Main yum Configuration
[ref]ruleThe gpgcheck option controls whether
RPM packages' signatures are always checked prior to installation.
To configure yum to check package signatures before installing
them, ensure the following line appears in /etc/yum.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). 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, 6.3.3, SRG-OS-000366-GPOS-00153, OL07-00-020050, SV-221710r877463_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q yum; then
# 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/yum.conf"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^gpgcheck\\>.*/$escaped_formatted_output/gi" "/etc/yum.conf"
else
if [[ -s "/etc/yum.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/yum.conf" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/yum.conf"
fi
printf '%s\n' "$formatted_output" >> "/etc/yum.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CJIS-5.10.4.1
- DISA-STIG-OL07-00-020050
- 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
- PCI-DSSv4-6.3.3
- 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/yum.conf
section: main
option: gpgcheck
value: 1
no_extra_spaces: true
create: false
when: '"yum" in ansible_facts.packages'
tags:
- CJIS-5.10.4.1
- DISA-STIG-OL07-00-020050
- 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
- PCI-DSSv4-6.3.3
- configure_strategy
- ensure_gpgcheck_globally_activated
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
|
Ensure gpgcheck Enabled for Local Packages
[ref]ruleyum should be configured to verify the signature(s) of local packages
prior to installation. To configure yum to verify signatures of local
packages, set the localpkg_gpgcheck to 1 in /etc/yum.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. 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, OL07-00-020060, SV-221711r877463_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q yum; then
# 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/yum.conf"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^localpkg_gpgcheck\\>.*/$escaped_formatted_output/gi" "/etc/yum.conf"
else
if [[ -s "/etc/yum.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/yum.conf" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/yum.conf"
fi
printf '%s\n' "$formatted_output" >> "/etc/yum.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- DISA-STIG-OL07-00-020060
- 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)
block:
- name: Check stats of yum
stat:
path: /etc/yum.conf
register: pkg
- name: Check if config file of yum is a symlink
ansible.builtin.set_fact:
pkg_config_file_symlink: '{{ pkg.stat.lnk_target if pkg.stat.lnk_target is match("^/.*")
else "/etc/yum.conf" | dirname ~ "/" ~ pkg.stat.lnk_target }}'
when: pkg.stat.lnk_target is defined
- name: Ensure GPG check Enabled for Local Packages (yum)
ini_file:
dest: '{{ pkg_config_file_symlink | default("/etc/yum.conf") }}'
section: main
option: localpkg_gpgcheck
value: 1
no_extra_spaces: true
create: true
when: '"yum" in ansible_facts.packages'
tags:
- DISA-STIG-OL07-00-020060
- 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 yum 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)." 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, 6.3.3, SRG-OS-000366-GPOS-00153 Remediation Shell script: (show)
sed -i 's/gpgcheck\s*=.*/gpgcheck=1/g' /etc/yum.repos.d/*
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Grep for yum repo section names
shell: |
set -o pipefail
grep -HEr '^\[.+\]' -r /etc/yum.repos.d/
register: repo_grep_results
failed_when: repo_grep_results.rc not in [0, 1]
changed_when: false
tags:
- 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
- PCI-DSSv4-6.3.3
- enable_strategy
- ensure_gpgcheck_never_disabled
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- name: Set gpgcheck=1 for each yum 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:
- 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
- PCI-DSSv4-6.3.3
- enable_strategy
- ensure_gpgcheck_never_disabled
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
|
Ensure Oracle Linux GPG Key Installed
[ref]ruleTo ensure the system can cryptographically verify base software
packages come from Oracle (and to connect to the Unbreakable Linux Network to
receive them), the Oracle GPG key must properly be installed.
To install the Oracle GPG key, run:
$ sudo uln_register
If the system is not connected to the Internet,
then install the Oracle GPG key from trusted media such as
the Oracle 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-oracle
Alternatively, the key may be pre-loaded during the Oracle installation. In
such cases, the key can be installed by running the following command:
sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-oracle 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 Oracle GPG key is necessary to
cryptographically verify packages are from Oracle. References:
11, 2, 3, 9, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, CCI-001749, 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), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, Req-6.2, OL07-00-010019, 1.2.2, SV-256975r902762_rule Remediation Shell script: (show)
# OL fingerprints below retrieved from: https://linux.oracle.com/security/gpg/#gpg
readonly OL_RELEASE_FINGERPRINT="42144123FECFC55B9086313D72F97B74EC551F03"
readonly OL_AUXILIARY_FINGERPRINT=""
FINGERPRINTS_REGEX="${OL_RELEASE_FINGERPRINT}"
if [[ -n "$OL_AUXILIARY_FINGERPRINT" ]]; then
FINGERPRINTS_REGEX+="|${OL_AUXILIARY_FINGERPRINT}"
fi
# Location of the key we would like to import (once it's integrity verified)
readonly OL_RELEASE_KEY="/etc/pki/rpm-gpg/RPM-GPG-KEY-oracle"
RPM_GPG_DIR_PERMS=$(stat -c %a "$(dirname "$OL_RELEASE_KEY")")
# Verify /etc/pki/rpm-gpg directory permissions are safe
if [ "${RPM_GPG_DIR_PERMS}" -le "755" ]
then
# If they are safe, try to obtain fingerprints from the key file
# (to ensure there won't be e.g. CRC error)
readarray -t GPG_OUT < <(gpg --with-fingerprint --with-colons "$OL_RELEASE_KEY" | grep "^fpr" | cut -d ":" -f 10)
GPG_RESULT=$?
# No CRC error, safe to proceed
if [ "${GPG_RESULT}" -eq "0" ]
then
# Filter just hexadecimal fingerprints from gpg's output from
# processing of a key file
echo "${GPG_OUT[*]}" | grep -vE "$FINGERPRINTS_REGEX" || {
# If $ OL_RELEASE_KEY file doesn't contain any keys with unknown fingerprint, import it
rpm --import "${OL_RELEASE_KEY}"
}
fi
fi
|
Ensure Software Patches Installed
[ref]rule
If the system is joined to the ULN
or a yum server, run the following command to install updates:
$ sudo yum update
If the system is not configured to use one of these sources, updates (in the form of RPM packages)
can be manually downloaded from the ULN and installed using rpm .
NOTE: U.S. Defense systems are required to be patched within 30 days or sooner as local policy
dictates.Warning:
The OVAL feed of Oracle Linux 7 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. 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, 6.3.3, SRG-OS-000480-GPOS-00227, OL07-00-020260, SV-221720r603260_rule 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:
- CJIS-5.10.4.1
- DISA-STIG-OL07-00-020260
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-2(5)
- NIST-800-53-SI-2(c)
- PCI-DSS-Req-6.2
- PCI-DSSv4-6.3.3
- 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
Oracle Linux 7. |
contains 20 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 12 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 5 rules |
Limit Password Reuse
[ref]ruleDo not allow users to reuse recent passwords. This can be accomplished by using the
remember option for the pam_unix or pam_pwhistory PAM modules. 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. Warning:
Newer versions of authselect contain an authselect feature to easily and properly
enable pam_pwhistory.so module. If this feature is not yet available in your
system, an authselect custom profile must be used to avoid integrity issues in PAM files. Rationale:Preventing re-use of previous passwords helps ensure that a compromised password is not
re-used by a user. 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, 3.5.8, CCI-000200, 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, 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)(e), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.5, 8.3.7, SRG-OS-000077-GPOS-00045 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_unix_remember='2'
if [ -f /usr/bin/authselect ]; then
if authselect list-features minimal | grep -q with-pwhistory; then
if ! authselect check; then
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."
exit 1
fi
authselect enable-feature with-pwhistory
authselect apply-changes -b
else
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1'"requisite"' \2/' "$PAM_FILE_PATH"
else
LAST_MATCH_LINE=$(grep -nP "^password.*requisite.*pam_pwquality\.so" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
if [ ! -z $LAST_MATCH_LINE ]; then
sed -i --follow-symlinks $LAST_MATCH_LINE' a password '"requisite"' pam_pwhistory.so' "$PAM_FILE_PATH"
else
echo 'password '"requisite"' pam_pwhistory.so' >> "$PAM_FILE_PATH"
fi
fi
fi
fi
else
if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*' "/etc/pam.d/system-auth"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "/etc/pam.d/system-auth")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1'"requisite"' \2/' "/etc/pam.d/system-auth"
else
LAST_MATCH_LINE=$(grep -nP "^password.*requisite.*pam_pwquality\.so" "/etc/pam.d/system-auth" | tail -n 1 | cut -d: -f 1)
if [ ! -z $LAST_MATCH_LINE ]; then
sed -i --follow-symlinks $LAST_MATCH_LINE' a password '"requisite"' pam_pwhistory.so' "/etc/pam.d/system-auth"
else
echo 'password '"requisite"' pam_pwhistory.so' >> "/etc/pam.d/system-auth"
fi
fi
fi
fi
PWHISTORY_CONF="/etc/security/pwhistory.conf"
if [ -f $PWHISTORY_CONF ]; then
regex="^\s*remember\s*="
line="remember = $var_password_pam_unix_remember"
if ! grep -q $regex $PWHISTORY_CONF; then
echo $line >> $PWHISTORY_CONF
else
sed -i --follow-symlinks 's|^\s*\(remember\s*=\s*\)\(\S\+\)|\1'"$var_password_pam_unix_remember"'|g' $PWHISTORY_CONF
fi
if [ -e "/etc/pam.d/system-auth" ] ; then
PAM_FILE_PATH="/etc/pam.d/system-auth"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*password\s.*\bpam_pwhistory.so\s.*\bremember\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*password.*pam_pwhistory.so.*)\bremember\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/system-auth was not found" >&2
fi
else
PAM_FILE_PATH="/etc/pam.d/system-auth"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1'"requisite"' \2/' "$PAM_FILE_PATH"
else
echo 'password '"requisite"' pam_pwhistory.so' >> "$PAM_FILE_PATH"
fi
fi
# Check the option
if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*\sremember\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks '/\s*password\s+'"requisite"'\s+pam_pwhistory.so.*/ s/$/ remember='"$var_password_pam_unix_remember"'/' "$PAM_FILE_PATH"
else
sed -i -E --follow-symlinks 's/(\s*password\s+'"requisite"'\s+pam_pwhistory.so\s+.*)('"remember"'=)[[:alnum:]]+\s*(.*)/\1\2'"$var_password_pam_unix_remember"' \3/' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CJIS-5.6.2.1.1
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_password_pam_unix_remember # promote to variable
set_fact:
var_password_pam_unix_remember: !!str 2
tags:
- always
- name: Limit Password Reuse - 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:
- CJIS-5.6.2.1.1
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - Collect the available authselect features
ansible.builtin.command:
cmd: authselect list-features minimal
register: result_authselect_available_features
changed_when: false
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CJIS-5.6.2.1.1
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - Enable pam_pwhistory.so using authselect feature
block:
- name: Limit Password Reuse - Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Limit Password Reuse - Informative message based on the authselect integrity
check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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: Limit Password Reuse - 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: Limit Password Reuse - Ensure "with-pwhistory" feature is enabled using
authselect tool
ansible.builtin.command:
cmd: authselect enable-feature with-pwhistory
register: result_authselect_enable_feature_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("with-pwhistory")
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_enable_feature_cmd is not skipped
- result_authselect_enable_feature_cmd is success
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
- result_authselect_available_features.stdout is search("with-pwhistory")
tags:
- CJIS-5.6.2.1.1
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - Enable pam_pwhistory.so in appropriate PAM files
block:
- name: Limit Password Reuse - Define the PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- name: Limit Password Reuse - Check if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
is present
block:
- name: Limit Password Reuse - Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Limit Password Reuse - Informative message based on the authselect integrity
check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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: Limit Password Reuse - 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: Limit Password Reuse - 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: Limit Password Reuse - 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: Limit Password Reuse - 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: Limit Password Reuse - Check if any custom profile with the same name
was already created
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: Limit Password Reuse - Create an authselect custom profile based on the
current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Limit Password Reuse - Ensure the authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Limit Password Reuse - Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Limit Password Reuse - Change the PAM file to be edited according to the
custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Limit Password Reuse - Check if expected PAM module line is present in {{
pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+requisite\s+pam_pwhistory.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
- name: Limit Password Reuse - Include or update the PAM module line in {{ pam_file_path
}}
block:
- name: Limit Password Reuse - Check if required PAM module line is present in
{{ pam_file_path }} with different control
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+.*\s+pam_pwhistory.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Limit Password Reuse - Ensure the correct control for the required PAM
module line in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: ^(\s*password\s+).*(\bpam_pwhistory.so.*)
replace: \1requisite \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Limit Password Reuse - Ensure the required PAM module line is included
in {{ pam_file_path }}
ansible.builtin.lineinfile:
dest: '{{ pam_file_path }}'
insertafter: ^password.*requisite.*pam_pwquality\.so
line: password requisite pam_pwhistory.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
when:
- '"pam" in ansible_facts.packages'
- |
(result_authselect_available_features.stdout is defined and result_authselect_available_features.stdout is not search("with-pwhistory")) or result_authselect_available_features is not defined
tags:
- CJIS-5.6.2.1.1
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - Check the presence of /etc/security/pwhistory.conf
file
ansible.builtin.stat:
path: /etc/security/pwhistory.conf
register: result_pwhistory_conf_check
when: '"pam" in ansible_facts.packages'
tags:
- CJIS-5.6.2.1.1
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - pam_pwhistory.so parameters are configured in /etc/security/pwhistory.conf
file
block:
- name: Limit Password Reuse - Ensure the pam_pwhistory.so remember parameter in
/etc/security/pwhistory.conf
ansible.builtin.lineinfile:
path: /etc/security/pwhistory.conf
regexp: ^\s*remember\s*=
line: remember = {{ var_password_pam_unix_remember }}
state: present
- name: Limit Password Reuse - Ensure the pam_pwhistory.so remember parameter is
removed from PAM files
block:
- name: Limit Password Reuse - Check if /etc/pam.d/system-auth file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
- name: Limit Password Reuse - Check the proper remediation for the system
block:
- name: Limit Password Reuse - Define the PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- name: Limit Password Reuse - Check if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
is present
block:
- name: Limit Password Reuse - Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Limit Password Reuse - Informative message based on the authselect
integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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: Limit Password Reuse - 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: Limit Password Reuse - 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: Limit Password Reuse - 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: Limit Password Reuse - 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: Limit Password Reuse - Check if any custom profile with the same name
was already created
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: Limit Password Reuse - Create an authselect custom profile based on
the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Limit Password Reuse - Ensure the authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Limit Password Reuse - Restore the authselect features in the custom
profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Limit Password Reuse - Change the PAM file to be edited according
to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Limit Password Reuse - Ensure the "remember" option from "pam_pwhistory.so"
is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*password.*pam_pwhistory.so.*)\bremember\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- result_pam_file_present.stat.exists
when:
- '"pam" in ansible_facts.packages'
- result_pwhistory_conf_check.stat.exists
tags:
- CJIS-5.6.2.1.1
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - pam_pwhistory.so parameters are configured in PAM files
block:
- name: Limit Password Reuse - Define the PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- name: Limit Password Reuse - Check if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
is present
block:
- name: Limit Password Reuse - Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Limit Password Reuse - Informative message based on the authselect integrity
check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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: Limit Password Reuse - 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: Limit Password Reuse - 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: Limit Password Reuse - 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: Limit Password Reuse - 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: Limit Password Reuse - Check if any custom profile with the same name
was already created
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: Limit Password Reuse - Create an authselect custom profile based on the
current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Limit Password Reuse - Ensure the authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Limit Password Reuse - Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Limit Password Reuse - Change the PAM file to be edited according to the
custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Limit Password Reuse - Check if expected PAM module line is present in {{
pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+requisite\s+pam_pwhistory.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
- name: Limit Password Reuse - Include or update the PAM module line in {{ pam_file_path
}}
block:
- name: Limit Password Reuse - Check if required PAM module line is present in
{{ pam_file_path }} with different control
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+.*\s+pam_pwhistory.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Limit Password Reuse - Ensure the correct control for the required PAM
module line in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: ^(\s*password\s+).*(\bpam_pwhistory.so.*)
replace: \1requisite \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Limit Password Reuse - Ensure the required PAM module line is included
in {{ pam_file_path }}
ansible.builtin.lineinfile:
dest: '{{ pam_file_path }}'
line: password requisite pam_pwhistory.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
- name: Limit Password Reuse - Check if the required PAM module option is present
in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+requisite\s+pam_pwhistory.so\s*.*\sremember\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module_remember_option_present
- name: Limit Password Reuse - Ensure the "remember" PAM option for "pam_pwhistory.so"
is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*password\s+requisite\s+pam_pwhistory.so.*)
line: \1 remember={{ var_password_pam_unix_remember }}
state: present
register: result_pam_remember_add
when:
- result_pam_module_remember_option_present.found == 0
- name: Limit Password Reuse - Ensure the required value for "remember" PAM option
from "pam_pwhistory.so" in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*password\s+requisite\s+pam_pwhistory.so\s+.*)(remember)=[0-9a-zA-Z]+\s*(.*)
line: \1\2={{ var_password_pam_unix_remember }} \3
register: result_pam_remember_edit
when:
- result_pam_module_remember_option_present.found > 0
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- (result_pam_remember_add is defined and result_pam_remember_add.changed) or
(result_pam_remember_edit is defined and result_pam_remember_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- not result_pwhistory_conf_check.stat.exists
tags:
- CJIS-5.6.2.1.1
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
|
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 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. 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, 8.3.4, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005, OL07-00-010320, SV-221690r880681_rule 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
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."
exit 1
fi
authselect enable-feature with-faillock
authselect apply-changes -b
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' "$pam_file"
sed -i --follow-symlinks '/^auth.*required.*pam_deny\.so.*/i auth required pam_faillock.so authfail' "$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
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
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*\(deny\s*=\s*\)\(\S\+\)|\1'"$var_accounts_passwords_pam_faillock_deny"'|g' $FAILLOCK_CONF
fi
for pam_file in "${AUTH_FILES[@]}"
do
if [ -e "$pam_file" ] ; then
PAM_FILE_PATH="$pam_file"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "$pam_file")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*auth\s.*\bpam_faillock.so\s.*\bdeny\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*auth.*pam_faillock.so.*)\bdeny\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "$pam_file was not found" >&2
fi
done
else
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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- 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:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- 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
failed_when: false
- name: Lock Accounts After Failed Password Attempts - Informative message based
on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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_enable_feature_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("with-faillock")
- name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_enable_feature_cmd is not skipped
- result_authselect_enable_feature_cmd is success
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- 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
insertbefore: ^auth.*required.*pam_deny\.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:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- 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:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- 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:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- 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 not in PAM files
block:
- name: Lock Accounts After Failed Password Attempts - Check if /etc/pam.d/system-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
- name: Lock Accounts After Failed Password Attempts - Check the proper remediation
for the system
block:
- name: Lock Accounts After Failed Password Attempts - Define the PAM file to
be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- 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
- name: Lock Accounts After Failed Password Attempts - Ensure authselect custom
profile is used if authselect 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
failed_when: false
- name: Lock Accounts After Failed Password Attempts - Informative message based
on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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
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: Lock Accounts After Failed Password Attempts - 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: Lock Accounts After Failed Password Attempts - 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: Lock Accounts After Failed Password Attempts - 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: Lock Accounts After Failed Password Attempts - Check if any custom profile
with the same name was already created
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: Lock Accounts After Failed Password Attempts - Create an authselect
custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Lock Accounts After Failed Password Attempts - Ensure the authselect
custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Lock Accounts After Failed Password Attempts - Restore the authselect
features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Lock Accounts After Failed Password Attempts - Change the PAM file to
be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Lock Accounts After Failed Password Attempts - Ensure the "deny" option
from "pam_faillock.so" is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*auth.*pam_faillock.so.*)\bdeny\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- result_pam_file_present.stat.exists
- name: Lock Accounts After Failed Password Attempts - Check if /etc/pam.d/password-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/password-auth
register: result_pam_file_present
- name: Lock Accounts After Failed Password Attempts - Check the proper remediation
for the system
block:
- name: Lock Accounts After Failed Password Attempts - Define the PAM file to
be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/password-auth
- 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
- name: Lock Accounts After Failed Password Attempts - Ensure authselect custom
profile is used if authselect 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
failed_when: false
- name: Lock Accounts After Failed Password Attempts - Informative message based
on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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
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: Lock Accounts After Failed Password Attempts - 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: Lock Accounts After Failed Password Attempts - 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: Lock Accounts After Failed Password Attempts - 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: Lock Accounts After Failed Password Attempts - Check if any custom profile
with the same name was already created
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: Lock Accounts After Failed Password Attempts - Create an authselect
custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Lock Accounts After Failed Password Attempts - Ensure the authselect
custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Lock Accounts After Failed Password Attempts - Restore the authselect
features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Lock Accounts After Failed Password Attempts - Change the PAM file to
be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Lock Accounts After Failed Password Attempts - Ensure the "deny" option
from "pam_faillock.so" is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*auth.*pam_faillock.so.*)\bdeny\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- result_pam_file_present.stat.exists
when:
- '"pam" in ansible_facts.packages'
- result_faillock_conf_check.stat.exists
tags:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- 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:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- 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 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. 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, OL07-00-010330, SV-221691r880684_rule 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
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."
exit 1
fi
authselect enable-feature with-faillock
authselect apply-changes -b
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.*required.*pam_deny\.so.*/i 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
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
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 >> $FAILLOCK_CONF
fi
for pam_file in "${AUTH_FILES[@]}"
do
if [ -e "$pam_file" ] ; then
PAM_FILE_PATH="$pam_file"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "$pam_file")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*auth\s.*\bpam_faillock.so\s.*\beven_deny_root\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*auth.*pam_faillock.so.*)\beven_deny_root\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "$pam_file was not found" >&2
fi
done
else
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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- DISA-STIG-OL07-00-010330
- 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:
- DISA-STIG-OL07-00-010330
- 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
failed_when: false
- 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.rc == 0
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_enable_feature_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("with-faillock")
- name: Configure the root Account for Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_enable_feature_cmd is not skipped
- result_authselect_enable_feature_cmd is success
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- DISA-STIG-OL07-00-010330
- 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
insertbefore: ^auth.*required.*pam_deny\.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:
- DISA-STIG-OL07-00-010330
- 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:
- DISA-STIG-OL07-00-010330
- 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:
- DISA-STIG-OL07-00-010330
- 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 not in PAM files
block:
- name: Configure the root Account for Failed Password Attempts - Check if /etc/pam.d/system-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
- name: Configure the root Account for Failed Password Attempts - Check the proper
remediation for the system
block:
- name: Configure the root Account for Failed Password Attempts - Define the PAM
file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- 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
- name: Configure the root Account for Failed Password Attempts - Ensure authselect
custom profile is used if authselect 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
failed_when: false
- 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.rc == 0
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 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: Configure the root Account for Failed Password Attempts - 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: Configure the root Account for Failed Password Attempts - 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: Configure the root Account for Failed Password Attempts - 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: Configure the root Account for Failed Password Attempts - Check if any
custom profile with the same name was already created
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: Configure the root Account for Failed Password Attempts - Create an
authselect custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Configure the root Account for Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Configure the root Account for Failed Password Attempts - Ensure the
authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Configure the root Account for Failed Password Attempts - Restore the
authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Configure the root Account for Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Configure the root Account for Failed Password Attempts - Change the
PAM file to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Configure the root Account for Failed Password Attempts - Ensure the "even_deny_root"
option from "pam_faillock.so" is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*auth.*pam_faillock.so.*)\beven_deny_root\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Configure the root Account for Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- result_pam_file_present.stat.exists
- name: Configure the root Account for Failed Password Attempts - Check if /etc/pam.d/password-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/password-auth
register: result_pam_file_present
- name: Configure the root Account for Failed Password Attempts - Check the proper
remediation for the system
block:
- name: Configure the root Account for Failed Password Attempts - Define the PAM
file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/password-auth
- 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
- name: Configure the root Account for Failed Password Attempts - Ensure authselect
custom profile is used if authselect 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
failed_when: false
- 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.rc == 0
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 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: Configure the root Account for Failed Password Attempts - 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: Configure the root Account for Failed Password Attempts - 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: Configure the root Account for Failed Password Attempts - 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: Configure the root Account for Failed Password Attempts - Check if any
custom profile with the same name was already created
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: Configure the root Account for Failed Password Attempts - Create an
authselect custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Configure the root Account for Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Configure the root Account for Failed Password Attempts - Ensure the
authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Configure the root Account for Failed Password Attempts - Restore the
authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Configure the root Account for Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Configure the root Account for Failed Password Attempts - Change the
PAM file to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Configure the root Account for Failed Password Attempts - Ensure the "even_deny_root"
option from "pam_faillock.so" is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*auth.*pam_faillock.so.*)\beven_deny_root\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Configure the root Account for Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- result_pam_file_present.stat.exists
when:
- '"pam" in ansible_facts.packages'
- result_faillock_conf_check.stat.exists
tags:
- DISA-STIG-OL07-00-010330
- 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:
- DISA-STIG-OL07-00-010330
- 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. 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. 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, OL07-00-010320, SV-221690r880681_rule 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
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."
exit 1
fi
authselect enable-feature with-faillock
authselect apply-changes -b
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.*required.*pam_deny\.so.*/i 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
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
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*\(fail_interval\s*=\s*\)\(\S\+\)|\1'"$var_accounts_passwords_pam_faillock_fail_interval"'|g' $FAILLOCK_CONF
fi
for pam_file in "${AUTH_FILES[@]}"
do
if [ -e "$pam_file" ] ; then
PAM_FILE_PATH="$pam_file"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "$pam_file")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*auth\s.*\bpam_faillock.so\s.*\bfail_interval\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*auth.*pam_faillock.so.*)\bfail_interval\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "$pam_file was not found" >&2
fi
done
else
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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- DISA-STIG-OL07-00-010320
- 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:
- DISA-STIG-OL07-00-010320
- 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
failed_when: false
- 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.rc == 0
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_enable_feature_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("with-faillock")
- name: Set Interval For Counting Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_enable_feature_cmd is not skipped
- result_authselect_enable_feature_cmd is success
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- DISA-STIG-OL07-00-010320
- 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
insertbefore: ^auth.*required.*pam_deny\.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:
- DISA-STIG-OL07-00-010320
- 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:
- DISA-STIG-OL07-00-010320
- 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:
- DISA-STIG-OL07-00-010320
- 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 not in PAM files
block:
- name: Set Interval For Counting Failed Password Attempts - Check if /etc/pam.d/system-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
- name: Set Interval For Counting Failed Password Attempts - Check the proper remediation
for the system
block:
- name: Set Interval For Counting Failed Password Attempts - Define the PAM file
to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- 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
- name: Set Interval For Counting Failed Password Attempts - Ensure authselect
custom profile is used if authselect 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
failed_when: false
- 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.rc == 0
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 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: Set Interval For Counting Failed Password Attempts - 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: Set Interval For Counting Failed Password Attempts - 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: Set Interval For Counting Failed Password Attempts - 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: Set Interval For Counting Failed Password Attempts - Check if any custom
profile with the same name was already created
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: Set Interval For Counting Failed Password Attempts - Create an authselect
custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Set Interval For Counting Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Set Interval For Counting Failed Password Attempts - Ensure the authselect
custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Set Interval For Counting Failed Password Attempts - Restore the authselect
features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Set Interval For Counting Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Set Interval For Counting Failed Password Attempts - Change the PAM
file to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Set Interval For Counting Failed Password Attempts - Ensure the "fail_interval"
option from "pam_faillock.so" is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*auth.*pam_faillock.so.*)\bfail_interval\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Set Interval For Counting Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- result_pam_file_present.stat.exists
- name: Set Interval For Counting Failed Password Attempts - Check if /etc/pam.d/password-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/password-auth
register: result_pam_file_present
- name: Set Interval For Counting Failed Password Attempts - Check the proper remediation
for the system
block:
- name: Set Interval For Counting Failed Password Attempts - Define the PAM file
to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/password-auth
- 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
- name: Set Interval For Counting Failed Password Attempts - Ensure authselect
custom profile is used if authselect 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
failed_when: false
- 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.rc == 0
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 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: Set Interval For Counting Failed Password Attempts - 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: Set Interval For Counting Failed Password Attempts - 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: Set Interval For Counting Failed Password Attempts - 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: Set Interval For Counting Failed Password Attempts - Check if any custom
profile with the same name was already created
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: Set Interval For Counting Failed Password Attempts - Create an authselect
custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Set Interval For Counting Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Set Interval For Counting Failed Password Attempts - Ensure the authselect
custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Set Interval For Counting Failed Password Attempts - Restore the authselect
features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Set Interval For Counting Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Set Interval For Counting Failed Password Attempts - Change the PAM
file to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Set Interval For Counting Failed Password Attempts - Ensure the "fail_interval"
option from "pam_faillock.so" is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*auth.*pam_faillock.so.*)\bfail_interval\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Set Interval For Counting Failed Password Attempts - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- result_pam_file_present.stat.exists
when:
- '"pam" in ansible_facts.packages'
- result_faillock_conf_check.stat.exists
tags:
- DISA-STIG-OL07-00-010320
- 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:
- DISA-STIG-OL07-00-010320
- 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.
If unlock_time is set to 0 , manual intervention by an administrator is required
to unlock a user. This should be done using the faillock tool. Warning:
If the system supports the new /etc/security/faillock.conf file but the
pam_faillock.so parameters are defined directly in /etc/pam.d/system-auth and
/etc/pam.d/password-auth , the remediation will migrate the unlock_time parameter
to /etc/security/faillock.conf to ensure compatibility with authselect tool.
The parameters deny and fail_interval , if used, also have to be migrated
by their respective remediation. 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. 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, 8.3.4, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005, OL07-00-010320, SV-221690r880681_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_accounts_passwords_pam_faillock_unlock_time='900'
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
authselect enable-feature with-faillock
authselect apply-changes -b
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.*required.*pam_deny\.so.*/i 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
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
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*\(unlock_time\s*=\s*\)\(\S\+\)|\1'"$var_accounts_passwords_pam_faillock_unlock_time"'|g' $FAILLOCK_CONF
fi
for pam_file in "${AUTH_FILES[@]}"
do
if [ -e "$pam_file" ] ; then
PAM_FILE_PATH="$pam_file"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "$pam_file")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*auth\s.*\bpam_faillock.so\s.*\bunlock_time\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*auth.*pam_faillock.so.*)\bunlock_time\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "$pam_file was not found" >&2
fi
done
else
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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- 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:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- 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
failed_when: false
- 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.rc == 0
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_enable_feature_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("with-faillock")
- name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_enable_feature_cmd is not skipped
- result_authselect_enable_feature_cmd is success
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- 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
insertbefore: ^auth.*required.*pam_deny\.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:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- 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 900
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:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- 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:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- 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 not in PAM files
block:
- name: Set Lockout Time for Failed Password Attempts - Check if /etc/pam.d/system-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
- name: Set Lockout Time for Failed Password Attempts - Check the proper remediation
for the system
block:
- name: Set Lockout Time for Failed Password Attempts - Define the PAM file to
be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- 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
- name: Set Lockout Time for Failed Password Attempts - Ensure authselect custom
profile is used if authselect 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
failed_when: false
- 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.rc == 0
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
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: Set Lockout Time for Failed Password Attempts - 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: Set Lockout Time for Failed Password Attempts - 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: Set Lockout Time for Failed Password Attempts - 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: Set Lockout Time for Failed Password Attempts - Check if any custom
profile with the same name was already created
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: Set Lockout Time for Failed Password Attempts - Create an authselect
custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Set Lockout Time for Failed Password Attempts - Ensure the authselect
custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Set Lockout Time for Failed Password Attempts - Restore the authselect
features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Set Lockout Time for Failed Password Attempts - Change the PAM file
to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Set Lockout Time for Failed Password Attempts - Ensure the "unlock_time"
option from "pam_faillock.so" is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*auth.*pam_faillock.so.*)\bunlock_time\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- result_pam_file_present.stat.exists
- name: Set Lockout Time for Failed Password Attempts - Check if /etc/pam.d/password-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/password-auth
register: result_pam_file_present
- name: Set Lockout Time for Failed Password Attempts - Check the proper remediation
for the system
block:
- name: Set Lockout Time for Failed Password Attempts - Define the PAM file to
be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/password-auth
- 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
- name: Set Lockout Time for Failed Password Attempts - Ensure authselect custom
profile is used if authselect 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
failed_when: false
- 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.rc == 0
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
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: Set Lockout Time for Failed Password Attempts - 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: Set Lockout Time for Failed Password Attempts - 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: Set Lockout Time for Failed Password Attempts - 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: Set Lockout Time for Failed Password Attempts - Check if any custom
profile with the same name was already created
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: Set Lockout Time for Failed Password Attempts - Create an authselect
custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Set Lockout Time for Failed Password Attempts - Ensure the authselect
custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Set Lockout Time for Failed Password Attempts - Restore the authselect
features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Set Lockout Time for Failed Password Attempts - Change the PAM file
to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Set Lockout Time for Failed Password Attempts - Ensure the "unlock_time"
option from "pam_faillock.so" is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*auth.*pam_faillock.so.*)\bunlock_time\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- result_pam_file_present.stat.exists
when:
- '"pam" in ansible_facts.packages'
- result_faillock_conf_check.stat.exists
tags:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- 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:
- CJIS-5.5.3
- DISA-STIG-OL07-00-010320
- NIST-800-171-3.1.8
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- 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 5 rules |
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 5 rules |
Ensure PAM Enforces Password Requirements - Minimum Digit Characters
[ref]ruleThe pam_pwquality module's dcredit parameter controls requirements for
usage of digits in a password. When set to a negative number, any password will be required to
contain that many digits. When set to a positive number, pam_pwquality will grant +1 additional
length credit for each digit. Modify the dcredit setting in
/etc/security/pwquality.conf to require the use of a digit in passwords. Rationale:Use of a complex password helps to increase the time and resources required
to compromise the password. Password complexity, or strength, is a measure of
the effectiveness of a password in resisting attempts at guessing and brute-force
attacks.
Password complexity is one factor of several that determines how long it takes
to crack a password. The more complex the password, the greater the number of
possible combinations that need to be tested before the password is compromised.
Requiring digits makes password guessing attacks more difficult by ensuring a larger
search space. References:
BP28(R18), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000194, 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_SMF_EXT.1, Req-8.2.3, 8.3.6, 8.3.9, SRG-OS-000071-GPOS-00039, OL07-00-010140, SV-221671r603260_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_dcredit='-1'
if [ -e "/etc/pam.d/system-auth" ] ; then
PAM_FILE_PATH="/etc/pam.d/system-auth"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bdcredit\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bdcredit\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/system-auth was not found" >&2
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=$(sed 's/[\^=\$,;+]*//g' <<< "^dcredit")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_dcredit"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^dcredit\\>" "/etc/security/pwquality.conf"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^dcredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
fi
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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- DISA-STIG-OL07-00-010140
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_password_pam_dcredit # promote to variable
set_fact:
var_password_pam_dcredit: !!str -1
tags:
- always
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Check
if /etc/pam.d/system-auth file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
when: '"pam" in ansible_facts.packages'
tags:
- DISA-STIG-OL07-00-010140
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Check
the proper remediation for the system
block:
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Define
the PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Check
if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Ensure
authselect custom profile is used if authselect is present
block:
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
Informative message based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
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: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
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: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
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: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
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: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
Check if any custom profile with the same name was already created
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: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
Create an authselect custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
Ensure the authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
Change the PAM file to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Ensure
the "dcredit" option from "pam_pwquality.so" is not present in {{ pam_file_path
}}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*password.*pam_pwquality.so.*)\bdcredit\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Ensure
authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- '"pam" in ansible_facts.packages'
- result_pam_file_present.stat.exists
tags:
- DISA-STIG-OL07-00-010140
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Ensure
PAM variable dcredit is set accordingly
ansible.builtin.lineinfile:
create: true
dest: /etc/security/pwquality.conf
regexp: ^#?\s*dcredit
line: dcredit = {{ var_password_pam_dcredit }}
when: '"pam" in ansible_facts.packages'
tags:
- DISA-STIG-OL07-00-010140
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
[ref]ruleThe pam_pwquality module's lcredit parameter controls requirements for
usage of lowercase letters in a password. When set to a negative number, any password will be required to
contain that many lowercase characters. When set to a positive number, pam_pwquality will grant +1 additional
length credit for each lowercase character. Modify the lcredit setting in
/etc/security/pwquality.conf to require the use of a lowercase character in passwords. Rationale:Use of a complex password helps to increase the time and resources required
to compromise the password. Password complexity, or strength, is a measure of
the effectiveness of a password in resisting attempts at guessing and brute-force
attacks.
Password complexity is one factor of several that determines how long it takes
to crack a password. The more complex the password, the greater the number of
possble combinations that need to be tested before the password is compromised.
Requiring a minimum number of lowercase characters makes password guessing attacks
more difficult by ensuring a larger search space. References:
BP28(R18), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000193, 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_SMF_EXT.1, Req-8.2.3, 8.3.6, 8.3.9, SRG-OS-000070-GPOS-00038, OL07-00-010130, SV-221670r603260_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_lcredit='-1'
if [ -e "/etc/pam.d/system-auth" ] ; then
PAM_FILE_PATH="/etc/pam.d/system-auth"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\blcredit\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\blcredit\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/system-auth was not found" >&2
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=$(sed 's/[\^=\$,;+]*//g' <<< "^lcredit")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_lcredit"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^lcredit\\>" "/etc/security/pwquality.conf"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^lcredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
fi
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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- DISA-STIG-OL07-00-010130
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_password_pam_lcredit # promote to variable
set_fact:
var_password_pam_lcredit: !!str -1
tags:
- always
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters -
Check if /etc/pam.d/system-auth file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
when: '"pam" in ansible_facts.packages'
tags:
- DISA-STIG-OL07-00-010130
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters -
Check the proper remediation for the system
block:
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Define the PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Check if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Ensure authselect custom profile is used if authselect is present
block:
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Informative message based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Check if any custom profile with the same name was already created
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: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Create an authselect custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Ensure the authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Change the PAM file to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Ensure the "lcredit" option from "pam_pwquality.so" is not present in {{ pam_file_path
}}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*password.*pam_pwquality.so.*)\blcredit\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
- Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- '"pam" in ansible_facts.packages'
- result_pam_file_present.stat.exists
tags:
- DISA-STIG-OL07-00-010130
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters -
Ensure PAM variable lcredit is set accordingly
ansible.builtin.lineinfile:
create: true
dest: /etc/security/pwquality.conf
regexp: ^#?\s*lcredit
line: lcredit = {{ var_password_pam_lcredit }}
when: '"pam" in ansible_facts.packages'
tags:
- DISA-STIG-OL07-00-010130
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
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=18
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
compromise the password. 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_SMF_EXT.1, Req-8.2.3, 8.3.6, 8.3.9, SRG-OS-000078-GPOS-00046, OL07-00-010280, SV-221686r603260_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_minlen='18'
if [ -e "/etc/pam.d/system-auth" ] ; then
PAM_FILE_PATH="/etc/pam.d/system-auth"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bminlen\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bminlen\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/system-auth was not found" >&2
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" "$var_password_pam_minlen"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^minlen\\>" "/etc/security/pwquality.conf"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^minlen\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
fi
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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CJIS-5.6.2.1.1
- DISA-STIG-OL07-00-010280
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- 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 18
tags:
- always
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Check if /etc/pam.d/system-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
when: '"pam" in ansible_facts.packages'
tags:
- CJIS-5.6.2.1.1
- DISA-STIG-OL07-00-010280
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Check the proper
remediation for the system
block:
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Define the
PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Check if system
relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure authselect
custom profile is used if authselect is present
block:
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Check integrity
of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Informative
message based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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: Ensure PAM Enforces Password Requirements - Minimum Length - 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: Ensure PAM Enforces Password Requirements - Minimum Length - 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: Ensure PAM Enforces Password Requirements - Minimum Length - 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: Ensure PAM Enforces Password Requirements - Minimum Length - 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: Ensure PAM Enforces Password Requirements - Minimum Length - Check if
any custom profile with the same name was already created
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: Ensure PAM Enforces Password Requirements - Minimum Length - Create an
authselect custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure the
authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Ensure PAM Enforces Password Requirements - Minimum Length - Restore the
authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Change the
PAM file to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure the
"minlen" option from "pam_pwquality.so" is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*password.*pam_pwquality.so.*)\bminlen\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- '"pam" in ansible_facts.packages'
- result_pam_file_present.stat.exists
tags:
- CJIS-5.6.2.1.1
- DISA-STIG-OL07-00-010280
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure PAM variable
minlen is set accordingly
ansible.builtin.lineinfile:
create: true
dest: /etc/security/pwquality.conf
regexp: ^#?\s*minlen
line: minlen = {{ var_password_pam_minlen }}
when: '"pam" in ansible_facts.packages'
tags:
- CJIS-5.6.2.1.1
- DISA-STIG-OL07-00-010280
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure PAM Enforces Password Requirements - Minimum Special Characters
[ref]ruleThe pam_pwquality module's ocredit= parameter controls requirements for
usage of special (or "other") characters in a password. When set to a negative number,
any password will be required to contain that many special characters.
When set to a positive number, pam_pwquality will grant +1
additional length credit for each special character. Modify the ocredit setting
in /etc/security/pwquality.conf to equal -1
to require use of a special character in passwords. Rationale:Use of a complex password helps to increase the time and resources required
to compromise the password. Password complexity, or strength, is a measure of
the effectiveness of a password in resisting attempts at guessing and brute-force
attacks.
Password complexity is one factor of several that determines how long it takes
to crack a password. The more complex the password, the greater the number of
possible combinations that need to be tested before the password is compromised.
Requiring a minimum number of special characters makes password guessing attacks
more difficult by ensuring a larger search space. References:
BP28(R18), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-001619, 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_SMF_EXT.1, SRG-OS-000266-GPOS-00101, OL07-00-010150, SV-221672r603260_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_ocredit='-1'
if [ -e "/etc/pam.d/system-auth" ] ; then
PAM_FILE_PATH="/etc/pam.d/system-auth"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bocredit\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bocredit\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/system-auth was not found" >&2
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=$(sed 's/[\^=\$,;+]*//g' <<< "^ocredit")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_ocredit"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^ocredit\\>" "/etc/security/pwquality.conf"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^ocredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
fi
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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- DISA-STIG-OL07-00-010150
- 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)
- accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_password_pam_ocredit # promote to variable
set_fact:
var_password_pam_ocredit: !!str -1
tags:
- always
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters - Check
if /etc/pam.d/system-auth file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
when: '"pam" in ansible_facts.packages'
tags:
- DISA-STIG-OL07-00-010150
- 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)
- accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters - Check
the proper remediation for the system
block:
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters -
Define the PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters -
Check if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters -
Ensure authselect custom profile is used if authselect is present
block:
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- Informative message based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- Check if any custom profile with the same name was already created
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: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- Create an authselect custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- Ensure the authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
- Change the PAM file to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters -
Ensure the "ocredit" option from "pam_pwquality.so" is not present in {{ pam_file_path
}}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*password.*pam_pwquality.so.*)\bocredit\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters -
Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- '"pam" in ansible_facts.packages'
- result_pam_file_present.stat.exists
tags:
- DISA-STIG-OL07-00-010150
- 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)
- accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters - Ensure
PAM variable ocredit is set accordingly
ansible.builtin.lineinfile:
create: true
dest: /etc/security/pwquality.conf
regexp: ^#?\s*ocredit
line: ocredit = {{ var_password_pam_ocredit }}
when: '"pam" in ansible_facts.packages'
tags:
- DISA-STIG-OL07-00-010150
- 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)
- accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
[ref]ruleThe pam_pwquality module's ucredit= parameter controls requirements for
usage of uppercase letters in a password. When set to a negative number, any password will be required to
contain that many uppercase characters. When set to a positive number, pam_pwquality will grant +1 additional
length credit for each uppercase character. Modify the ucredit setting in
/etc/security/pwquality.conf to require the use of an uppercase character in passwords. Rationale:Use of a complex password helps to increase the time and resources required to compromise the password.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts
at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more
complex the password, the greater the number of possible combinations that need to be tested before
the password is compromised. References:
BP28(R18), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000192, CCI-000193, 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_SMF_EXT.1, Req-8.2.3, 8.3.6, 8.3.9, SRG-OS-000069-GPOS-00037, SRG-OS-000070-GPOS-00038, OL07-00-010120, SV-221669r603260_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_ucredit='-1'
if [ -e "/etc/pam.d/system-auth" ] ; then
PAM_FILE_PATH="/etc/pam.d/system-auth"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bucredit\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bucredit\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/system-auth was not found" >&2
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=$(sed 's/[\^=\$,;+]*//g' <<< "^ucredit")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_ucredit"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^ucredit\\>" "/etc/security/pwquality.conf"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^ucredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
fi
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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- DISA-STIG-OL07-00-010120
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_password_pam_ucredit # promote to variable
set_fact:
var_password_pam_ucredit: !!str -1
tags:
- always
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters -
Check if /etc/pam.d/system-auth file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
when: '"pam" in ansible_facts.packages'
tags:
- DISA-STIG-OL07-00-010120
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters -
Check the proper remediation for the system
block:
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Define the PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Check if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Ensure authselect custom profile is used if authselect is present
block:
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Informative message based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- 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: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Check if any custom profile with the same name was already created
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: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Create an authselect custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Ensure the authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Change the PAM file to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Ensure the "ucredit" option from "pam_pwquality.so" is not present in {{ pam_file_path
}}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*password.*pam_pwquality.so.*)\bucredit\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
- Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- '"pam" in ansible_facts.packages'
- result_pam_file_present.stat.exists
tags:
- DISA-STIG-OL07-00-010120
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters -
Ensure PAM variable ucredit is set accordingly
ansible.builtin.lineinfile:
create: true
dest: /etc/security/pwquality.conf
regexp: ^#?\s*ucredit
line: ucredit = {{ var_password_pam_ucredit }}
when: '"pam" in ansible_facts.packages'
tags:
- DISA-STIG-OL07-00-010120
- 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
- PCI-DSSv4-8.3.6
- PCI-DSSv4-8.3.9
- accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Hashing Algorithm
[ref]groupThe system's default algorithm for storing password hashes in
/etc/shadow is SHA-512. This can be configured in several
locations. |
contains 1 rule |
Set PAM''s Password Hashing Algorithm
[ref]ruleThe PAM system service can be configured to only store encrypted
representations of passwords. In "/etc/pam.d/system-auth", the
password section of the file controls which PAM modules execute
during a password change. Set the pam_unix.so module in the
password section to include the argument sha512 , as shown
below:
password sufficient pam_unix.so sha512 other arguments...
This will help ensure when local users change their passwords, hashes for
the new passwords will be generated using the SHA-512 algorithm. This is
the default.Rationale:Passwords need to be protected at all times, and encryption is the standard
method for protecting passwords. If passwords are not encrypted, they can
be plainly read (i.e., clear text) and easily compromised. Passwords that
are encrypted with a weak algorithm are no more protected than if they are
kepy in plain text.
This setting ensures user and group account administration utilities are
configured to store only encrypted representations of passwords.
Additionally, the crypt_style configuration option ensures the use
of a strong hashing algorithm that makes password cracking attacks more
difficult. References:
BP28(R32), 1, 12, 15, 16, 5, 5.6.2.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.13.11, CCI-000196, CCI-000803, 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(c), IA-5(1)(c), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, 8.3.2, SRG-OS-000073-GPOS-00041, SRG-OS-000120-GPOS-00061, OL07-00-010200, SV-221677r880672_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
if [ -e "/etc/pam.d/system-auth" ] ; then
PAM_FILE_PATH="/etc/pam.d/system-auth"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if ! grep -qP '^\s*password\s+'"sufficient"'\s+pam_unix.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*password\s+.*\s+pam_unix.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_unix.so.*)/\1'"sufficient"' \2/' "$PAM_FILE_PATH"
else
echo 'password '"sufficient"' pam_unix.so' >> "$PAM_FILE_PATH"
fi
fi
# Check the option
if ! grep -qP '^\s*password\s+'"sufficient"'\s+pam_unix.so\s*.*\ssha512\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks '/\s*password\s+'"sufficient"'\s+pam_unix.so.*/ s/$/ sha512/' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/system-auth was not found" >&2
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CJIS-5.6.2.2
- DISA-STIG-OL07-00-010200
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- set_password_hashing_algorithm_systemauth
- name: Set PAM's Password Hashing Algorithm - Check if /etc/pam.d/system-auth file
is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
when: '"pam" in ansible_facts.packages'
tags:
- CJIS-5.6.2.2
- DISA-STIG-OL07-00-010200
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- set_password_hashing_algorithm_systemauth
- name: Set PAM's Password Hashing Algorithm - Check the proper remediation for the
system
block:
- name: Set PAM's Password Hashing Algorithm - Define the PAM file to be edited
as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- name: Set PAM's Password Hashing Algorithm - Check if system relies on authselect
tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Set PAM's Password Hashing Algorithm - Ensure authselect custom profile
is used if authselect is present
block:
- name: Set PAM's Password Hashing Algorithm - Check integrity of authselect current
profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Set PAM's Password Hashing Algorithm - Informative message based on the
authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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 PAM's Password Hashing Algorithm - 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: Set PAM's Password Hashing Algorithm - 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: Set PAM's Password Hashing Algorithm - 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: Set PAM's Password Hashing Algorithm - 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: Set PAM's Password Hashing Algorithm - Check if any custom profile with
the same name was already created
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: Set PAM's Password Hashing Algorithm - Create an authselect custom profile
based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Set PAM's Password Hashing Algorithm - Ensure the authselect custom profile
is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Set PAM's Password Hashing Algorithm - Restore the authselect features
in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Set PAM's Password Hashing Algorithm - Change the PAM file to be edited
according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Set PAM's Password Hashing Algorithm - Check if expected PAM module line
is present in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+sufficient\s+pam_unix.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
- name: Set PAM's Password Hashing Algorithm - Include or update the PAM module
line in {{ pam_file_path }}
block:
- name: Set PAM's Password Hashing Algorithm - Check if required PAM module line
is present in {{ pam_file_path }} with different control
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+.*\s+pam_unix.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Set PAM's Password Hashing Algorithm - Ensure the correct control for
the required PAM module line in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: ^(\s*password\s+).*(\bpam_unix.so.*)
replace: \1sufficient \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Set PAM's Password Hashing Algorithm - Ensure the required PAM module
line is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
dest: '{{ pam_file_path }}'
line: password sufficient pam_unix.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
- name: Set PAM's Password Hashing Algorithm - Check if the required PAM module
option is present in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+sufficient\s+pam_unix.so\s*.*\ssha512\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module_sha512_option_present
- name: Set PAM's Password Hashing Algorithm - Ensure the "sha512" PAM option for
"pam_unix.so" is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*password\s+sufficient\s+pam_unix.so.*)
line: \1 sha512
state: present
register: result_pam_sha512_add
when:
- result_pam_module_sha512_option_present.found == 0
- name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- |-
(result_pam_sha512_add is defined and result_pam_sha512_add.changed)
or (result_pam_sha512_edit is defined and result_pam_sha512_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- result_pam_file_present.stat.exists
tags:
- CJIS-5.6.2.2
- DISA-STIG-OL07-00-010200
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- set_password_hashing_algorithm_systemauth
|
Set Up a Private Namespace in PAM Configuration
[ref]ruleTo setup a private namespace add the following line to /etc/pam.d/login :
session required pam_namespace.so Rationale:The pam_namespace PAM module sets up a private namespace for a
session with polyinstantiated directories. A polyinstantiated directory
provides a different instance of itself based on user name, or when using
SELinux, user name, security context or both. The polyinstatied directories
can be used to dedicate separate temporary directories to each account. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) && rpm --quiet -q pam ); then
if ! grep -Eq '^\s*session\s+required\s+pam_namespace.so\s*$' '/etc/pam.d/login' ; then
echo "session required pam_namespace.so" >> "/etc/pam.d/login"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- enable_pam_namespace
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- name: Make changes to /etc/pam.d/login
lineinfile:
path: /etc/pam.d/login
create: false
regexp: ^\s*session\s+required\s+pam_namespace.so\s*$
line: session required pam_namespace.so
state: present
when: ( not ( lookup("env", "container") == "bwrap-osbuild" ) and "pam" in ansible_facts.packages
)
tags:
- enable_pam_namespace
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- 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 5 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 2 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 90
A value of 180 days is sufficient for many environments.
The DoD requirement is 60.
The profile requirement is 90 .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. 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, 8.3.10.1, SRG-OS-000076-GPOS-00044, OL07-00-010250, SV-221683r603260_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then
var_accounts_maximum_age_login_defs='90'
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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CJIS-5.6.2.1
- DISA-STIG-OL07-00-010250
- 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
- PCI-DSSv4-8.3.10.1
- 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 90
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:
- CJIS-5.6.2.1
- DISA-STIG-OL07-00-010250
- 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
- PCI-DSSv4-8.3.10.1
- accounts_maximum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Minimum Length in login.defs
[ref]ruleTo specify password length requirements for new accounts, edit the file
/etc/login.defs and add or correct the following line:
PASS_MIN_LEN 18
The DoD requirement is 15 .
The FISMA requirement is 12 .
The profile requirement is
18 .
If a program consults /etc/login.defs and also another PAM module
(such as pam_pwquality ) during a password change operation, then
the most restrictive must be satisfied. See PAM section for more
information about enforcing password quality requirements.Rationale:Requiring a minimum password length makes password
cracking attacks more difficult by ensuring a larger
search space. However, any security benefit from an onerous requirement
must be carefully weighed against usability problems, support costs, or counterproductive
behavior that may result. References:
BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.7, 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(f), IA-5(1)(a), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000078-GPOS-00046 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then
var_accounts_password_minlen_login_defs='18'
grep -q ^PASS_MIN_LEN /etc/login.defs && \
sed -i "s/PASS_MIN_LEN.*/PASS_MIN_LEN\t$var_accounts_password_minlen_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]
then
echo -e "PASS_MIN_LEN\t$var_accounts_password_minlen_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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CJIS-5.6.2.1
- NIST-800-171-3.5.7
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(f)
- accounts_password_minlen_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_password_minlen_login_defs # promote to variable
set_fact:
var_accounts_password_minlen_login_defs: !!str 18
tags:
- always
- name: Set Password Minimum Length in login.defs
lineinfile:
dest: /etc/login.defs
regexp: ^PASS_MIN_LEN *[0-9]*
state: present
line: PASS_MIN_LEN {{ var_accounts_password_minlen_login_defs }}
create: true
when: '"shadow-utils" in ansible_facts.packages'
tags:
- CJIS-5.6.2.1
- NIST-800-171-3.5.7
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(f)
- accounts_password_minlen_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 |
Set number of Password Hashing Rounds - password-auth
[ref]ruleConfigure the number or rounds for the password hashing algorithm. This can be
accomplished by using the rounds option for the pam_unix PAM module.
In file /etc/pam.d/password-auth append rounds=65536
to the pam_unix.so entry, as shown below:
password sufficient pam_unix.so ...existing_options... rounds=65536
The system's default number of rounds is 5000.Warning:
Setting a high number of hashing rounds makes it more difficult to brute force the password,
but requires more CPU resources to authenticate users. Rationale:Using a higher number of rounds makes password cracking attacks more difficult. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_unix_rounds='65536'
if [ -e "/etc/pam.d/password-auth" ] ; then
PAM_FILE_PATH="/etc/pam.d/password-auth"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/password-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if ! grep -qP '^\s*password\s+'"sufficient"'\s+pam_unix.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*password\s+.*\s+pam_unix.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_unix.so.*)/\1'"sufficient"' \2/' "$PAM_FILE_PATH"
else
echo 'password '"sufficient"' pam_unix.so' >> "$PAM_FILE_PATH"
fi
fi
# Check the option
if ! grep -qP '^\s*password\s+'"sufficient"'\s+pam_unix.so\s*.*\srounds\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks '/\s*password\s+'"sufficient"'\s+pam_unix.so.*/ s/$/ rounds='"$var_password_pam_unix_rounds"'/' "$PAM_FILE_PATH"
else
sed -i -E --follow-symlinks 's/(\s*password\s+'"sufficient"'\s+pam_unix.so\s+.*)('"rounds"'=)[[:alnum:]]+\s*(.*)/\1\2'"$var_password_pam_unix_rounds"' \3/' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/password-auth was not found" >&2
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- accounts_password_pam_unix_rounds_password_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_password_pam_unix_rounds # promote to variable
set_fact:
var_password_pam_unix_rounds: !!str 65536
tags:
- always
- name: Set number of Password Hashing Rounds - password-auth - Check if /etc/pam.d/password-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/password-auth
register: result_pam_file_present
when: '"pam" in ansible_facts.packages'
tags:
- accounts_password_pam_unix_rounds_password_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Set number of Password Hashing Rounds - password-auth - Check the proper remediation
for the system
block:
- name: Set number of Password Hashing Rounds - password-auth - Define the PAM file
to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/password-auth
- name: Set number of Password Hashing Rounds - password-auth - Check if system
relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Set number of Password Hashing Rounds - password-auth - Ensure authselect
custom profile is used if authselect is present
block:
- name: Set number of Password Hashing Rounds - password-auth - Check integrity
of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Set number of Password Hashing Rounds - password-auth - Informative message
based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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 number of Password Hashing Rounds - password-auth - 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: Set number of Password Hashing Rounds - password-auth - 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: Set number of Password Hashing Rounds - password-auth - 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: Set number of Password Hashing Rounds - password-auth - 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: Set number of Password Hashing Rounds - password-auth - Check if any custom
profile with the same name was already created
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: Set number of Password Hashing Rounds - password-auth - Create an authselect
custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Set number of Password Hashing Rounds - password-auth - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Set number of Password Hashing Rounds - password-auth - Ensure the authselect
custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Set number of Password Hashing Rounds - password-auth - Restore the authselect
features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Set number of Password Hashing Rounds - password-auth - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Set number of Password Hashing Rounds - password-auth - Change the PAM
file to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Set number of Password Hashing Rounds - password-auth - Check if expected
PAM module line is present in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+sufficient\s+pam_unix.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
- name: Set number of Password Hashing Rounds - password-auth - Include or update
the PAM module line in {{ pam_file_path }}
block:
- name: Set number of Password Hashing Rounds - password-auth - Check if required
PAM module line is present in {{ pam_file_path }} with different control
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+.*\s+pam_unix.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Set number of Password Hashing Rounds - password-auth - Ensure the correct
control for the required PAM module line in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: ^(\s*password\s+).*(\bpam_unix.so.*)
replace: \1sufficient \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Set number of Password Hashing Rounds - password-auth - Ensure the required
PAM module line is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
dest: '{{ pam_file_path }}'
line: password sufficient pam_unix.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Set number of Password Hashing Rounds - password-auth - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
- name: Set number of Password Hashing Rounds - password-auth - Check if the required
PAM module option is present in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+sufficient\s+pam_unix.so\s*.*\srounds\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module_rounds_option_present
- name: Set number of Password Hashing Rounds - password-auth - Ensure the "rounds"
PAM option for "pam_unix.so" is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*password\s+sufficient\s+pam_unix.so.*)
line: \1 rounds={{ var_password_pam_unix_rounds }}
state: present
register: result_pam_rounds_add
when:
- result_pam_module_rounds_option_present.found == 0
- name: Set number of Password Hashing Rounds - password-auth - Ensure the required
value for "rounds" PAM option from "pam_unix.so" in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*password\s+sufficient\s+pam_unix.so\s+.*)(rounds)=[0-9a-zA-Z]+\s*(.*)
line: \1\2={{ var_password_pam_unix_rounds }} \3
register: result_pam_rounds_edit
when:
- result_pam_module_rounds_option_present.found > 0
- name: Set number of Password Hashing Rounds - password-auth - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- |-
(result_pam_rounds_add is defined and result_pam_rounds_add.changed)
or (result_pam_rounds_edit is defined and result_pam_rounds_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- result_pam_file_present.stat.exists
tags:
- accounts_password_pam_unix_rounds_password_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
|
Set number of Password Hashing Rounds - system-auth
[ref]ruleConfigure the number or rounds for the password hashing algorithm. This can be
accomplished by using the rounds option for the pam_unix PAM module.
In file /etc/pam.d/system-auth append rounds=65536
to the pam_unix.so entry, as shown below:
password sufficient pam_unix.so ...existing_options... rounds=65536
The system's default number of rounds is 5000.Warning:
Setting a high number of hashing rounds makes it more difficult to brute force the password,
but requires more CPU resources to authenticate users. Rationale:Using a higher number of rounds makes password cracking attacks more difficult. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_unix_rounds='65536'
if [ -e "/etc/pam.d/system-auth" ] ; then
PAM_FILE_PATH="/etc/pam.d/system-auth"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
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."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# 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"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if ! grep -qP '^\s*password\s+'"sufficient"'\s+pam_unix.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*password\s+.*\s+pam_unix.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_unix.so.*)/\1'"sufficient"' \2/' "$PAM_FILE_PATH"
else
echo 'password '"sufficient"' pam_unix.so' >> "$PAM_FILE_PATH"
fi
fi
# Check the option
if ! grep -qP '^\s*password\s+'"sufficient"'\s+pam_unix.so\s*.*\srounds\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks '/\s*password\s+'"sufficient"'\s+pam_unix.so.*/ s/$/ rounds='"$var_password_pam_unix_rounds"'/' "$PAM_FILE_PATH"
else
sed -i -E --follow-symlinks 's/(\s*password\s+'"sufficient"'\s+pam_unix.so\s+.*)('"rounds"'=)[[:alnum:]]+\s*(.*)/\1\2'"$var_password_pam_unix_rounds"' \3/' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/system-auth was not found" >&2
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- accounts_password_pam_unix_rounds_system_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_password_pam_unix_rounds # promote to variable
set_fact:
var_password_pam_unix_rounds: !!str 65536
tags:
- always
- name: Set number of Password Hashing Rounds - system-auth - Check if /etc/pam.d/system-auth
file is present
ansible.builtin.stat:
path: /etc/pam.d/system-auth
register: result_pam_file_present
when: '"pam" in ansible_facts.packages'
tags:
- accounts_password_pam_unix_rounds_system_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Set number of Password Hashing Rounds - system-auth - Check the proper remediation
for the system
block:
- name: Set number of Password Hashing Rounds - system-auth - Define the PAM file
to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/system-auth
- name: Set number of Password Hashing Rounds - system-auth - Check if system relies
on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Set number of Password Hashing Rounds - system-auth - Ensure authselect
custom profile is used if authselect is present
block:
- name: Set number of Password Hashing Rounds - system-auth - Check integrity
of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Set number of Password Hashing Rounds - system-auth - Informative message
based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
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 number of Password Hashing Rounds - system-auth - 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: Set number of Password Hashing Rounds - system-auth - 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: Set number of Password Hashing Rounds - system-auth - 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: Set number of Password Hashing Rounds - system-auth - 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: Set number of Password Hashing Rounds - system-auth - Check if any custom
profile with the same name was already created
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: Set number of Password Hashing Rounds - system-auth - Create an authselect
custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Set number of Password Hashing Rounds - system-auth - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-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: Set number of Password Hashing Rounds - system-auth - Ensure the authselect
custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
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: Set number of Password Hashing Rounds - system-auth - Restore the authselect
features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Set number of Password Hashing Rounds - system-auth - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Set number of Password Hashing Rounds - system-auth - Change the PAM file
to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Set number of Password Hashing Rounds - system-auth - Check if expected
PAM module line is present in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+sufficient\s+pam_unix.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
- name: Set number of Password Hashing Rounds - system-auth - Include or update
the PAM module line in {{ pam_file_path }}
block:
- name: Set number of Password Hashing Rounds - system-auth - Check if required
PAM module line is present in {{ pam_file_path }} with different control
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+.*\s+pam_unix.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Set number of Password Hashing Rounds - system-auth - Ensure the correct
control for the required PAM module line in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: ^(\s*password\s+).*(\bpam_unix.so.*)
replace: \1sufficient \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Set number of Password Hashing Rounds - system-auth - Ensure the required
PAM module line is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
dest: '{{ pam_file_path }}'
line: password sufficient pam_unix.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Set number of Password Hashing Rounds - system-auth - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
- name: Set number of Password Hashing Rounds - system-auth - Check if the required
PAM module option is present in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+sufficient\s+pam_unix.so\s*.*\srounds\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module_rounds_option_present
- name: Set number of Password Hashing Rounds - system-auth - Ensure the "rounds"
PAM option for "pam_unix.so" is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*password\s+sufficient\s+pam_unix.so.*)
line: \1 rounds={{ var_password_pam_unix_rounds }}
state: present
register: result_pam_rounds_add
when:
- result_pam_module_rounds_option_present.found == 0
- name: Set number of Password Hashing Rounds - system-auth - Ensure the required
value for "rounds" PAM option from "pam_unix.so" in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*password\s+sufficient\s+pam_unix.so\s+.*)(rounds)=[0-9a-zA-Z]+\s*(.*)
line: \1\2={{ var_password_pam_unix_rounds }} \3
register: result_pam_rounds_edit
when:
- result_pam_module_rounds_option_present.found > 0
- name: Set number of Password Hashing Rounds - system-auth - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- |-
(result_pam_rounds_add is defined and result_pam_rounds_add.changed)
or (result_pam_rounds_edit is defined and result_pam_rounds_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- result_pam_file_present.stat.exists
tags:
- accounts_password_pam_unix_rounds_system_auth
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
|
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 1 rule |
Direct root Logins Not Allowed
[ref]ruleTo further limit access to the root account, administrators
can disable root logins at the console by editing the /etc/securetty file.
This file lists all devices the root user is allowed to login to. If the file does
not exist at all, the root user can login through any communication device on the
system, whether via the console or via a raw network interface. This is dangerous
as user can login to the system as root via Telnet, which sends the password in
plain text over the network. By default, Oracle Linux 7's
/etc/securetty file only allows the root user to login at the console
physically attached to the system. To prevent root from logging in, remove the
contents of this file. To prevent direct root logins, remove the contents of this
file by typing the following command:
$ sudo echo > /etc/securetty
Warning:
This rule only checks the /etc/securetty file existence and its content.
If you need to restrict user access using the /etc/securetty file, make sure
the pam_securetty.so PAM module is properly enabled in relevant PAM files. Rationale:Disabling direct root logins ensures proper accountability and multifactor
authentication to privileged accounts. Users will first login, then escalate
to privileged (root) access via su / sudo. This is required for FISMA Low
and FISMA Moderate systems. References:
BP28(R19), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.1, 3.1.6, 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, 4.3.3.7.4, 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, 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, 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, CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, 8.6.1 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
echo > /etc/securetty
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Direct root Logins Not Allowed
copy:
dest: /etc/securetty
content: ''
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.1
- NIST-800-171-3.1.6
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-2
- PCI-DSSv4-8.6.1
- low_complexity
- low_disruption
- medium_severity
- no_direct_root_logins
- no_reboot_needed
- restrict_strategy
|
Secure Session Configuration Files for Login Accounts
[ref]groupWhen a user logs into a Unix account, the system
configures the user's session by reading a number of files. Many of
these files are located in the user's home directory, and may have
weak permissions as a result of user error or misconfiguration. If
an attacker can modify or even read certain types of account
configuration information, they can often gain full access to the
affected user's account. Therefore, it is important to test and
correct configuration file permissions for interactive accounts,
particularly those of privileged users such as root or system
administrators. |
contains 3 rules |
Configure Polyinstantiation of /tmp Directories
[ref]ruleTo configure polyinstantiated /tmp directories, first create the parent directories
which will hold the polyinstantiation child directories. Use the following command:
$ sudo mkdir --mode 000 /tmp/tmp-inst
Then, add the following entry to /etc/security/namespace.conf :
/tmp /tmp/tmp-inst/ level root,adm Rationale:Polyinstantiation of temporary directories is a proactive security measure
which reduces chances of attacks that are made possible by /tmp
directories being world-writable. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ! ( [ "${container:-}" == "bwrap-osbuild" ] ); then
#!/bin/bash
# shellcheck disable=SC2174
mkdir -p --mode 000 /tmp/tmp-inst
chmod 000 /tmp/tmp-inst
chcon --reference=/tmp /tmp/tmp-inst
if ! grep -Eq '^\s*/tmp\s+/tmp/tmp-inst/\s+level\s+root,adm$' /etc/security/namespace.conf ; then
if grep -Eq '^\s*/tmp\s+' /etc/security/namespace.conf ; then
sed -i '/^\s*\/tmp/d' /etc/security/namespace.conf
fi
echo "/tmp /tmp/tmp-inst/ level root,adm" >> /etc/security/namespace.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure Polyinstantiation of /var/tmp Directories
[ref]ruleTo configure polyinstantiated /tmp directories, first create the parent directories
which will hold the polyinstantiation child directories. Use the following command:
$ sudo mkdir --mode 000 /var/tmp/tmp-inst
Then, add the following entry to /etc/security/namespace.conf :
/var/tmp /var/tmp/tmp-inst/ level root,adm Rationale:Polyinstantiation of temporary directories is a proactive security measure
which reduces chances of attacks that are made possible by /var/tmp
directories being world-writable. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ! ( [ "${container:-}" == "bwrap-osbuild" ] ); then
#!/bin/bash
# shellcheck disable=SC2174
mkdir -p --mode 000 /var/tmp/tmp-inst
chmod 000 /var/tmp/tmp-inst
chcon --reference=/var/tmp /var/tmp/tmp-inst
if ! grep -Eq '^\s*/var/tmp\s+/var/tmp/tmp-inst/\s+level\s+root,adm$' /etc/security/namespace.conf ; then
if grep -Eq '^\s*/var/tmp\s+' /etc/security/namespace.conf ; then
sed -i '/^\s*\/var\/tmp/d' /etc/security/namespace.conf
fi
echo "/var/tmp /var/tmp/tmp-inst/ level root,adm" >> /etc/security/namespace.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Interactive Session Timeout
[ref]ruleSetting the TMOUT option in /etc/profile ensures that
all user sessions will terminate based on inactivity.
The value of TMOUT should be exported and read only.
The TMOUT
setting in a file loaded by /etc/profile or /etc/bashrc , e.g.
/etc/profile.d/tmout.sh should read as follows:
declare -xr TMOUT=600 Rationale:Terminating an idle session within a short time period reduces
the window of opportunity for unauthorized personnel to take control of a
management session enabled on the console or console port that has been
left unattended. References:
BP28(R29), 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.11, CCI-000057, CCI-001133, CCI-002361, 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, CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-12, SC-10, AC-2(5), CM-6(a), PR.AC-7, FMT_MOF_EXT.1, 8.6.1, SRG-OS-000163-GPOS-00072, SRG-OS-000029-GPOS-00010, OL07-00-040160, SV-221841r858463_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_accounts_tmout='600'
# if 0, no occurence of tmout found, if 1, occurence found
tmout_found=0
for f in /etc/profile /etc/profile.d/*.sh /etc/bashrc; do
if grep --silent '^[^#].*TMOUT' $f; then
sed -i -E "s/^(.*)TMOUT\s*=\s*(\w|\$)*(.*)$/declare -xr TMOUT=$var_accounts_tmout\3/g" $f
tmout_found=1
fi
done
if [ $tmout_found -eq 0 ]; then
echo -e "\n# Set TMOUT to $var_accounts_tmout per security requirements" >> /etc/profile.d/tmout.sh
echo "declare -xr TMOUT=$var_accounts_tmout" >> /etc/profile.d/tmout.sh
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_accounts_tmout # promote to variable
set_fact:
var_accounts_tmout: !!str 600
tags:
- always
- name: Correct any occurrence of TMOUT in /etc/bashrc
replace:
path: /etc/bashrc
regexp: ^[^#].*TMOUT=.*
replace: declare -xr TMOUT={{ var_accounts_tmout }}
register: bashrc_replaced
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040160
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSSv4-8.6.1
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Correct any occurrence of TMOUT in /etc/profile
replace:
path: /etc/profile
regexp: ^[^#].*TMOUT=.*
replace: declare -xr TMOUT={{ var_accounts_tmout }}
register: profile_replaced
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040160
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSSv4-8.6.1
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Interactive Session Timeout
lineinfile:
path: /etc/profile.d/tmout.sh
create: true
regexp: TMOUT=
line: declare -xr TMOUT={{ var_accounts_tmout }}
state: present
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- profile_replaced is defined and not profile_replaced.changed and bashrc_replaced
is defined and not bashrc_replaced.changed
tags:
- DISA-STIG-OL07-00-040160
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSSv4-8.6.1
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
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 Red Hat Enterprise Linux 7 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 1 rule |
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 1 rule |
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 - sudo
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands 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 a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/sudo -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 a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/sudo -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. References:
BP28(R19), 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-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), 4.3.2.6.7, 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-000466-GPOS-00210, OL07-00-030690, SV-221809r833067_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/sudo -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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- DISA-STIG-OL07-00-030690
- 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_privileged_commands_sudo
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/sudo
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/sudo -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/sudo -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/sudo -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/sudo -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/sudo -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/sudo -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'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-030690
- 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_privileged_commands_sudo
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
GRUB2 bootloader configuration
[ref]groupDuring the boot process, the boot loader is
responsible for starting the execution of the kernel and passing
options to it. The boot loader allows for the selection of
different kernels - possibly on different partitions or media.
The default Oracle Linux 7 boot loader for x86 systems is called GRUB2.
Options it can pass to the kernel include single-user mode, which
provides root access without any authentication, and the ability to
disable SELinux. To prevent local users from modifying the boot
parameters and endangering security, protect the boot loader configuration
with a password and ensure its configuration file's permissions
are set properly. |
contains 8 rules |
Non-UEFI GRUB2 bootloader configuration
[ref]groupNon-UEFI GRUB2 bootloader configuration |
contains 1 rule |
Set Boot Loader Password in grub2
[ref]ruleThe grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.
Since plaintext passwords are a security risk, generate a hash for the password
by running the following command:
# grub2-setpassword
When prompted, enter the password that was selected.
Warning:
To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation
must be automated as a component of machine provisioning, or followed manually as outlined above.
Also, do NOT manually add the superuser account and password to the
grub.cfg file as the grub2-mkconfig command overwrites this file. Rationale:Password protection on the boot loader configuration ensures
users with physical access cannot trivially alter
important bootloader settings. These include which kernel to use,
and whether to enter single-user mode. References:
BP28(R17), 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, 3.4.5, 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, 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, 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, OL07-00-010482, SV-221700r744071_rule |
UEFI GRUB2 bootloader configuration
[ref]groupUEFI GRUB2 bootloader configuration |
contains 1 rule |
Set the UEFI Boot Loader Password
[ref]ruleThe grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.
Since plaintext passwords are a security risk, generate a hash for the password
by running the following command:
# grub2-setpassword
When prompted, enter the password that was selected.
Warning:
To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation
must be automated as a component of machine provisioning, or followed manually as outlined above.
Also, do NOT manually add the superuser account and password to the
grub.cfg file as the grub2-mkconfig command overwrites this file. Rationale:Password protection on the boot loader configuration ensures
users with physical access cannot trivially alter
important bootloader settings. These include which kernel to use,
and whether to enter single-user mode. References:
BP28(R17), 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 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, 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, CM-6(a), PR.AC-4, PR.AC-6, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048, OL07-00-010491, SV-221702r744074_rule |
Configure L1 Terminal Fault mitigations
[ref]ruleL1 Terminal Fault (L1TF) is a hardware vulnerability which allows unprivileged
speculative access to data which is available in the Level 1 Data Cache when
the page table entry isn't present.
Select the appropriate mitigation by adding the argument
l1tf=full,force to the default
GRUB 2 command line for the Linux operating system.
To ensure that l1tf=full,force is added as a kernel command line
argument to newly installed kernels, add l1tf=full,force to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... l1tf=full,force ..."
Run the following command to update command line for already installed kernels:# grubby --update-kernel=ALL --args="l1tf=full,force"
Since Linux Kernel 4.19 you can check the L1TF vulnerability state with the
following command:
cat /sys/devices/system/cpu/vulnerabilities/l1tf Warning:
Enabling L1TF mitigations may impact performance of the system. Rationale:The L1TF vulnerability allows an attacker to bypass memory access security controls imposed
by the system or hypervisor. The L1TF vulnerability allows read access to any physical memory
location that is cached in the L1 Data Cache. Remediation script: (show)
[customizations.kernel]
append = "l1tf=full,force"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
var_l1tf_options='full,force'
# Correct the form of default kernel command line in GRUB
if grep -q '^GRUB_CMDLINE_LINUX=.*l1tf=.*"' '/etc/default/grub' ; then
# modify the GRUB command-line if an l1tf= arg already exists
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)l1tf=[^[:space:]]\+\(.*\"\)/\1l1tf=$var_l1tf_options\2/" '/etc/default/grub'
else
# no l1tf=arg is present, append it
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)\"/\1 l1tf=$var_l1tf_options\"/" '/etc/default/grub'
fi
grubby --update-kernel=ALL --args=l1tf=$var_l1tf_options
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- grub2_l1tf_argument
- high_severity
- low_disruption
- medium_complexity
- reboot_required
- restrict_strategy
- name: XCCDF Value var_l1tf_options # promote to variable
set_fact:
var_l1tf_options: !!str full,force
tags:
- always
- name: Check l1tf argument exists
command: grep 'GRUB_CMDLINE_LINUX.*l1tf=' /etc/default/grub
failed_when: false
register: argcheck
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_l1tf_argument
- high_severity
- low_disruption
- medium_complexity
- reboot_required
- restrict_strategy
- name: Replace existing l1tf argument
replace:
path: /etc/default/grub
regexp: l1tf=\w+
replace: l1tf={{ var_l1tf_options }}
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc == 0
tags:
- grub2_l1tf_argument
- high_severity
- low_disruption
- medium_complexity
- reboot_required
- restrict_strategy
- name: Add l1tf argument
replace:
path: /etc/default/grub
regexp: (GRUB_CMDLINE_LINUX=.*)"
replace: \1 l1tf={{ var_l1tf_options }}"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc != 0
tags:
- grub2_l1tf_argument
- high_severity
- low_disruption
- medium_complexity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /sbin/grubby --update-kernel=ALL --args="l1tf={{ var_l1tf_options }}"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_l1tf_argument
- high_severity
- low_disruption
- medium_complexity
- reboot_required
- restrict_strategy
|
Force kernel panic on uncorrected MCEs
[ref]ruleA Machine Check Exception is an error generated by the CPU itdetects an error
in itself, memory or I/O devices.
These errors may be corrected and generate a check log entry, if an error
cannot be corrected the kernel may panic or SIGBUS.
To force the kernel to panic on any uncorrected error reported by Machine Check
set the MCE tolerance to zero by adding mce=0
to the default GRUB 2 command line for the Linux operating system.
To ensure that mce=0 is added as a kernel command line
argument to newly installed kernels, add mce=0 to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... mce=0 ..."
Run the following command to update command line for already installed kernels:# grubby --update-kernel=ALL --args="mce=0" Rationale:Allowing uncorrected errors to result on a SIGBUS may allow an attacker to continue
trying to exploit a vulnerability such as Rowhammer. Remediation script: (show)
[customizations.kernel]
append = "mce=0"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# Correct the form of default kernel command line in GRUB
if grep -q '^GRUB_CMDLINE_LINUX=.*mce=.*"' '/etc/default/grub' ; then
# modify the GRUB command-line if an mce= arg already exists
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)mce=[^[:space:]]\+\(.*\"\)/\1mce=0\2/" '/etc/default/grub'
else
# no mce=arg is present, append it
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)\"/\1 mce=0\"/" '/etc/default/grub'
fi
grubby --update-kernel=ALL --args=mce=0
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- grub2_mce_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Check mce argument exists
command: grep 'GRUB_CMDLINE_LINUX.*mce=' /etc/default/grub
failed_when: false
register: argcheck
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_mce_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Replace existing mce argument
replace:
path: /etc/default/grub
regexp: mce=\w+
replace: mce=0
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc == 0
tags:
- grub2_mce_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Add mce argument
replace:
path: /etc/default/grub
regexp: (GRUB_CMDLINE_LINUX=.*)"
replace: \1 mce=0"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc != 0
tags:
- grub2_mce_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /sbin/grubby --update-kernel=ALL --args="mce=0"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_mce_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
|
Configure the confidence in TPM for entropy
[ref]ruleThe TPM security chip that is available in most modern systems has a hardware RNG.
It is also used to feed the entropy pool, but generally not credited entropy.
Use rng_core.default_quality in the kernel command line to set the trust
level on the hardware generators. The trust level defines the amount of entropy to credit.
A value of 0 tells the system not to trust the hardware random number generators
available, and doesn't credit any entropy to the pool.
A value of 1000 assigns full confidence in the generators, and credits all the
entropy it provides to the pool.
Note that the value of rng_core.default_quality is global, affecting the trust
on all hardware random number generators.
Select the appropriate confidence by adding the argument
rng_core.default_quality=500 to the default
GRUB 2 command line for the Linux operating system.
To ensure that rng_core.default_quality=500 is added as a kernel command line
argument to newly installed kernels, add rng_core.default_quality=500 to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... rng_core.default_quality=500 ..."
Run the following command to update command line for already installed kernels:# grubby --update-kernel=ALL --args="rng_core.default_quality=500" Rationale:A system may struggle to initialize its entropy pool and end up starving. Crediting entropy
from the hardware number generators available in the system helps fill up the entropy pool. Remediation script: (show)
[customizations.kernel]
append = "rng_core.default_quality=500"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
var_rng_core_default_quality='500'
# Correct the form of default kernel command line in GRUB
if grep -q '^GRUB_CMDLINE_LINUX=.*rng_core.default_quality=.*"' '/etc/default/grub' ; then
# modify the GRUB command-line if an rng_core.default_quality= arg already exists
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)rng_core.default_quality=[^[:space:]]\+\(.*\"\)/\1rng_core.default_quality=$var_rng_core_default_quality\2/" '/etc/default/grub'
else
# no rng_core.default_quality=arg is present, append it
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)\"/\1 rng_core.default_quality=$var_rng_core_default_quality\"/" '/etc/default/grub'
fi
grubby --update-kernel=ALL --args=rng_core.default_quality=$var_rng_core_default_quality
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- grub2_rng_core_default_quality_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: XCCDF Value var_rng_core_default_quality # promote to variable
set_fact:
var_rng_core_default_quality: !!str 500
tags:
- always
- name: Check rng_core.default_quality argument exists
command: grep 'GRUB_CMDLINE_LINUX.*rng_core.default_quality=' /etc/default/grub
failed_when: false
register: argcheck
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_rng_core_default_quality_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Replace existing rng_core.default_quality argument
replace:
path: /etc/default/grub
regexp: rng_core.default_quality=\w+
replace: rng_core.default_quality={{ var_rng_core_default_quality }}
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc == 0
tags:
- grub2_rng_core_default_quality_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Add rng_core.default_quality argument
replace:
path: /etc/default/grub
regexp: (GRUB_CMDLINE_LINUX=.*)"
replace: \1 rng_core.default_quality={{ var_rng_core_default_quality }}"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc != 0
tags:
- grub2_rng_core_default_quality_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /sbin/grubby --update-kernel=ALL --args="rng_core.default_quality={{ var_rng_core_default_quality
}}"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_rng_core_default_quality_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
|
Disable merging of slabs with similar size
[ref]ruleThe kernel may merge similar slabs together to reduce overhead and increase
cache hotness of objects.
Disabling merging of slabs keeps the slabs separate and reduces the risk of
kernel heap overflows overwriting objects in merged caches.
To disable merging of slabs in the Kernel add the argument slab_nomerge=yes
to the default GRUB 2 command line for the Linux operating system.
To ensure that slab_nomerge=yes is added as a kernel command line
argument to newly installed kernels, add slab_nomerge=yes to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... slab_nomerge=yes ..."
Run the following command to update command line for already installed kernels:# grubby --update-kernel=ALL --args="slab_nomerge=yes" Warning:
Disabling merge of slabs will slightly increase kernel memory utilization. Rationale:Disabling the merge of slabs of similar sizes prevents the kernel from
merging a seemingly useless but vulnerable slab with a useful and valuable slab.
This increase the risk that a heap overflow could overwrite objects from merged caches,
with unmerged caches the heap overflow would only affect the objects in the same cache.
Overall, this reduces the kernel attack surface area by isolating slabs from each other. Remediation script: (show)
[customizations.kernel]
append = "slab_nomerge=yes"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# Correct the form of default kernel command line in GRUB
if grep -q '^GRUB_CMDLINE_LINUX=.*slab_nomerge=.*"' '/etc/default/grub' ; then
# modify the GRUB command-line if an slab_nomerge= arg already exists
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)slab_nomerge=[^[:space:]]\+\(.*\"\)/\1slab_nomerge=yes\2/" '/etc/default/grub'
else
# no slab_nomerge=arg is present, append it
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)\"/\1 slab_nomerge=yes\"/" '/etc/default/grub'
fi
grubby --update-kernel=ALL --args=slab_nomerge=yes
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- grub2_slab_nomerge_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Check slab_nomerge argument exists
command: grep 'GRUB_CMDLINE_LINUX.*slab_nomerge=' /etc/default/grub
failed_when: false
register: argcheck
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_slab_nomerge_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Replace existing slab_nomerge argument
replace:
path: /etc/default/grub
regexp: slab_nomerge=\w+
replace: slab_nomerge=yes
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc == 0
tags:
- grub2_slab_nomerge_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Add slab_nomerge argument
replace:
path: /etc/default/grub
regexp: (GRUB_CMDLINE_LINUX=.*)"
replace: \1 slab_nomerge=yes"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc != 0
tags:
- grub2_slab_nomerge_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /sbin/grubby --update-kernel=ALL --args="slab_nomerge=yes"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_slab_nomerge_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
|
Configure Speculative Store Bypass Mitigation
[ref]ruleCertain CPUs are vulnerable to an exploit against a common wide industry wide performance
optimization known as Speculative Store Bypass (SSB).
In such cases, recent stores to the same memory location cannot always be observed by later
loads during speculative execution. However, such stores are unlikely and thus they can be
detected prior to instruction retirement at the end of a particular speculation execution
window.
Since Linux Kernel 4.17 you can check the SSB mitigation state with the following command:
cat /sys/devices/system/cpu/vulnerabilities/spec_store_bypass
Select the appropriate SSB state by adding the argument
spec_store_bypass_disable=seccomp to the default
GRUB 2 command line for the Linux operating system.
To ensure that spec_store_bypass_disable=seccomp is added as a kernel command line
argument to newly installed kernels, add spec_store_bypass_disable=seccomp to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... spec_store_bypass_disable=seccomp ..."
Run the following command to update command line for already installed kernels:# grubby --update-kernel=ALL --args="spec_store_bypass_disable=seccomp" Warning:
Disabling Speculative Store Bypass may impact performance of the system. Rationale:In vulnerable processsors, the speculatively forwarded store can be used in a cache side channel
attack. An example of this is reading memory to which the attacker does not directly have access,
for example inside the sandboxed code. Remediation script: (show)
[customizations.kernel]
append = "spec_store_bypass_disable=seccomp"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
var_spec_store_bypass_disable_options='seccomp'
# Correct the form of default kernel command line in GRUB
if grep -q '^GRUB_CMDLINE_LINUX=.*spec_store_bypass_disable=.*"' '/etc/default/grub' ; then
# modify the GRUB command-line if an spec_store_bypass_disable= arg already exists
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)spec_store_bypass_disable=[^[:space:]]\+\(.*\"\)/\1spec_store_bypass_disable=$var_spec_store_bypass_disable_options\2/" '/etc/default/grub'
else
# no spec_store_bypass_disable=arg is present, append it
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)\"/\1 spec_store_bypass_disable=$var_spec_store_bypass_disable_options\"/" '/etc/default/grub'
fi
grubby --update-kernel=ALL --args=spec_store_bypass_disable=$var_spec_store_bypass_disable_options
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- grub2_spec_store_bypass_disable_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: XCCDF Value var_spec_store_bypass_disable_options # promote to variable
set_fact:
var_spec_store_bypass_disable_options: !!str seccomp
tags:
- always
- name: Check spec_store_bypass_disable argument exists
command: grep 'GRUB_CMDLINE_LINUX.*spec_store_bypass_disable=' /etc/default/grub
failed_when: false
register: argcheck
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_spec_store_bypass_disable_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Replace existing spec_store_bypass_disable argument
replace:
path: /etc/default/grub
regexp: spec_store_bypass_disable=\w+
replace: spec_store_bypass_disable={{ var_spec_store_bypass_disable_options }}
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc == 0
tags:
- grub2_spec_store_bypass_disable_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Add spec_store_bypass_disable argument
replace:
path: /etc/default/grub
regexp: (GRUB_CMDLINE_LINUX=.*)"
replace: \1 spec_store_bypass_disable={{ var_spec_store_bypass_disable_options
}}"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc != 0
tags:
- grub2_spec_store_bypass_disable_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /sbin/grubby --update-kernel=ALL --args="spec_store_bypass_disable={{ var_spec_store_bypass_disable_options
}}"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_spec_store_bypass_disable_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
|
Enforce Spectre v2 mitigation
[ref]ruleSpectre V2 is an indirect branch poisoning attack that can lead to data leakage.
An exploit for Spectre V2 tricks the indirect branch predictor into executing
code from a future indirect branch chosen by the attacker, even if the privilege
level is different.
Since Linux Kernel 4.15 you can check the Spectre V2 mitigation state with the following command:
cat /sys/devices/system/cpu/vulnerabilities/spectre_v2
Enforce the Spectre V2 mitigation by adding the argument
spectre_v2=on to the default
GRUB 2 command line for the Linux operating system.
To ensure that spectre_v2=on) is added as a kernel command line
argument to newly installed kernels, add spectre_v2=on) to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... spectre_v2=on) ..."
Run the following command to update command line for already installed kernels:# grubby --update-kernel=ALL --args="spectre_v2=on)" Rationale:The Spectre V2 vulnerability allows an attacker to read memory that he should not have
access to. Remediation script: (show)
[customizations.kernel]
append = "spectre_v2=on"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# Correct the form of default kernel command line in GRUB
if grep -q '^GRUB_CMDLINE_LINUX=.*spectre_v2=.*"' '/etc/default/grub' ; then
# modify the GRUB command-line if an spectre_v2= arg already exists
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)spectre_v2=[^[:space:]]\+\(.*\"\)/\1spectre_v2=on\2/" '/etc/default/grub'
else
# no spectre_v2=arg is present, append it
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)\"/\1 spectre_v2=on\"/" '/etc/default/grub'
fi
grubby --update-kernel=ALL --args=spectre_v2=on
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- grub2_spectre_v2_argument
- high_severity
- low_disruption
- medium_complexity
- reboot_required
- restrict_strategy
- name: Check spectre_v2 argument exists
command: grep 'GRUB_CMDLINE_LINUX.*spectre_v2=' /etc/default/grub
failed_when: false
register: argcheck
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_spectre_v2_argument
- high_severity
- low_disruption
- medium_complexity
- reboot_required
- restrict_strategy
- name: Replace existing spectre_v2 argument
replace:
path: /etc/default/grub
regexp: spectre_v2=\w+
replace: spectre_v2=on
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc == 0
tags:
- grub2_spectre_v2_argument
- high_severity
- low_disruption
- medium_complexity
- reboot_required
- restrict_strategy
- name: Add spectre_v2 argument
replace:
path: /etc/default/grub
regexp: (GRUB_CMDLINE_LINUX=.*)"
replace: \1 spectre_v2=on"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- argcheck.rc != 0
tags:
- grub2_spectre_v2_argument
- high_severity
- low_disruption
- medium_complexity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /sbin/grubby --update-kernel=ALL --args="spectre_v2=on"
when:
- '"grub2-common" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- grub2_spectre_v2_argument
- high_severity
- low_disruption
- medium_complexity
- reboot_required
- restrict_strategy
|
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 37 rules |
The system includes support for Internet Protocol
version 6. A major and often-mentioned improvement over IPv4 is its
enormous increase in the number of available addresses. Another
important feature is its support for automatic configuration of
many network settings. |
contains 16 rules |
Configure IPv6 Settings if Necessary
[ref]groupA major feature of IPv6 is the extent to which systems
implementing it can automatically configure their networking
devices using information from the network. From a security
perspective, manually configuring important configuration
information is preferable to accepting it from the network
in an unauthenticated fashion. |
contains 16 rules |
Configure Accepting Default Router in Router Advertisements on All IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.accept_ra_defrtr kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_ra_defrtr=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.accept_ra_defrtr = 0 Rationale:An illicit router advertisement message could result in a man-in-the-middle attack. 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.ipv6.conf.all.accept_ra_defrtr from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_ra_defrtr.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.all.accept_ra_defrtr" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_all_accept_ra_defrtr_value='0'
#
# Set runtime for net.ipv6.conf.all.accept_ra_defrtr
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.accept_ra_defrtr="$sysctl_net_ipv6_conf_all_accept_ra_defrtr_value"
#
# If net.ipv6.conf.all.accept_ra_defrtr present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.accept_ra_defrtr = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_ra_defrtr")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_ra_defrtr_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 "^net.ipv6.conf.all.accept_ra_defrtr\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_ra_defrtr\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.accept_ra_defrtr.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra_defrtr
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.all.accept_ra_defrtr from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.accept_ra_defrtr
replace: '#net.ipv6.conf.all.accept_ra_defrtr'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra_defrtr
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_ra_defrtr_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_accept_ra_defrtr_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.accept_ra_defrtr is set
sysctl:
name: net.ipv6.conf.all.accept_ra_defrtr
value: '{{ sysctl_net_ipv6_conf_all_accept_ra_defrtr_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra_defrtr
- unknown_severity
|
Configure Accepting Prefix Information in Router Advertisements on All IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.accept_ra_pinfo kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_ra_pinfo=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.accept_ra_pinfo = 0 Rationale:An illicit router advertisement message could result in a man-in-the-middle attack. 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.ipv6.conf.all.accept_ra_pinfo from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_ra_pinfo.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.all.accept_ra_pinfo" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_all_accept_ra_pinfo_value='0'
#
# Set runtime for net.ipv6.conf.all.accept_ra_pinfo
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.accept_ra_pinfo="$sysctl_net_ipv6_conf_all_accept_ra_pinfo_value"
#
# If net.ipv6.conf.all.accept_ra_pinfo present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.accept_ra_pinfo = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_ra_pinfo")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_ra_pinfo_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 "^net.ipv6.conf.all.accept_ra_pinfo\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_ra_pinfo\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.accept_ra_pinfo.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra_pinfo
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.all.accept_ra_pinfo from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.accept_ra_pinfo
replace: '#net.ipv6.conf.all.accept_ra_pinfo'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra_pinfo
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_ra_pinfo_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_accept_ra_pinfo_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.accept_ra_pinfo is set
sysctl:
name: net.ipv6.conf.all.accept_ra_pinfo
value: '{{ sysctl_net_ipv6_conf_all_accept_ra_pinfo_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra_pinfo
- unknown_severity
|
Configure Accepting Router Preference in Router Advertisements on All IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.accept_ra_rtr_pref kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_ra_rtr_pref=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.accept_ra_rtr_pref = 0 Rationale:An illicit router advertisement message could result in a man-in-the-middle attack. 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.ipv6.conf.all.accept_ra_rtr_pref from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_ra_rtr_pref.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.all.accept_ra_rtr_pref" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_all_accept_ra_rtr_pref_value='0'
#
# Set runtime for net.ipv6.conf.all.accept_ra_rtr_pref
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.accept_ra_rtr_pref="$sysctl_net_ipv6_conf_all_accept_ra_rtr_pref_value"
#
# If net.ipv6.conf.all.accept_ra_rtr_pref present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.accept_ra_rtr_pref = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_ra_rtr_pref")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_ra_rtr_pref_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 "^net.ipv6.conf.all.accept_ra_rtr_pref\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_ra_rtr_pref\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.accept_ra_rtr_pref.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra_rtr_pref
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.all.accept_ra_rtr_pref from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.accept_ra_rtr_pref
replace: '#net.ipv6.conf.all.accept_ra_rtr_pref'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra_rtr_pref
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_ra_rtr_pref_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_accept_ra_rtr_pref_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.accept_ra_rtr_pref is set
sysctl:
name: net.ipv6.conf.all.accept_ra_rtr_pref
value: '{{ sysctl_net_ipv6_conf_all_accept_ra_rtr_pref_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_accept_ra_rtr_pref
- unknown_severity
|
Disable Accepting ICMP Redirects for All IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.accept_redirects = 0 Rationale:An illicit ICMP redirect message could result in a man-in-the-middle attack. References:
BP28(R22), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 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), CM-6(b), CM-6.1(iv), PR.IP-1, PR.PT-3, 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 net.ipv6.conf.all.accept_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.all.accept_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_all_accept_redirects_value='0'
#
# Set runtime for net.ipv6.conf.all.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.accept_redirects="$sysctl_net_ipv6_conf_all_accept_redirects_value"
#
# If net.ipv6.conf.all.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.accept_redirects = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_redirects_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 "^net.ipv6.conf.all.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.accept_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_redirects
- name: Comment out any occurrences of net.ipv6.conf.all.accept_redirects from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.accept_redirects
replace: '#net.ipv6.conf.all.accept_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_redirects
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.accept_redirects is set
sysctl:
name: net.ipv6.conf.all.accept_redirects
value: '{{ sysctl_net_ipv6_conf_all_accept_redirects_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_redirects
|
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router, which can
be used to bypass network security measures. This requirement applies only to the
forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and
the system is functioning as a router.
Accepting source-routed packets in the IPv6 protocol has few legitimate
uses. It should be disabled unless it is absolutely required. References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, 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.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.9.2.3, 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.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-040830, SV-221894r880666_rule 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.ipv6.conf.all.accept_source_route from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_source_route.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.all.accept_source_route" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_all_accept_source_route_value='0'
#
# Set runtime for net.ipv6.conf.all.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.accept_source_route="$sysctl_net_ipv6_conf_all_accept_source_route_value"
#
# If net.ipv6.conf.all.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.accept_source_route = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_source_route")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_source_route_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 "^net.ipv6.conf.all.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.accept_source_route.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040830
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_source_route
- name: Comment out any occurrences of net.ipv6.conf.all.accept_source_route from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.accept_source_route
replace: '#net.ipv6.conf.all.accept_source_route'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040830
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_source_route
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.accept_source_route is set
sysctl:
name: net.ipv6.conf.all.accept_source_route
value: '{{ sysctl_net_ipv6_conf_all_accept_source_route_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040830
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_source_route
|
Configure Auto Configuration on All IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.autoconf kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.autoconf=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.autoconf = 0 Rationale:An illicit router advertisement message could result in a man-in-the-middle attack. 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.ipv6.conf.all.autoconf from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.autoconf.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.all.autoconf" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_all_autoconf_value='0'
#
# Set runtime for net.ipv6.conf.all.autoconf
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.autoconf="$sysctl_net_ipv6_conf_all_autoconf_value"
#
# If net.ipv6.conf.all.autoconf present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.autoconf = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.autoconf")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_autoconf_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 "^net.ipv6.conf.all.autoconf\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.autoconf\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.autoconf.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_autoconf
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.all.autoconf from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.autoconf
replace: '#net.ipv6.conf.all.autoconf'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_autoconf
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_all_autoconf_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_autoconf_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.autoconf is set
sysctl:
name: net.ipv6.conf.all.autoconf
value: '{{ sysctl_net_ipv6_conf_all_autoconf_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_autoconf
- unknown_severity
|
Configure Maximum Number of Autoconfigured Addresses on All IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.max_addresses kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.max_addresses=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.max_addresses = 1 Rationale:The number of global unicast IPv6 addresses for each interface should be limited exactly to the number of statically configured addresses. 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.ipv6.conf.all.max_addresses from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.max_addresses.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.all.max_addresses" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_all_max_addresses_value='1'
#
# Set runtime for net.ipv6.conf.all.max_addresses
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.max_addresses="$sysctl_net_ipv6_conf_all_max_addresses_value"
#
# If net.ipv6.conf.all.max_addresses present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.max_addresses = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.max_addresses")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_max_addresses_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 "^net.ipv6.conf.all.max_addresses\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.max_addresses\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.max_addresses.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_max_addresses
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.all.max_addresses from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.max_addresses
replace: '#net.ipv6.conf.all.max_addresses'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_max_addresses
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_all_max_addresses_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_max_addresses_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.max_addresses is set
sysctl:
name: net.ipv6.conf.all.max_addresses
value: '{{ sysctl_net_ipv6_conf_all_max_addresses_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_max_addresses
- unknown_severity
|
Configure Denying Router Solicitations on All IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.router_solicitations kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.router_solicitations=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.router_solicitations = 0 Rationale:To prevent discovery of the system by other systems, router solicitation requests should be denied. 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.ipv6.conf.all.router_solicitations from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.router_solicitations.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.all.router_solicitations" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_all_router_solicitations_value='0'
#
# Set runtime for net.ipv6.conf.all.router_solicitations
#
/sbin/sysctl -q -n -w net.ipv6.conf.all.router_solicitations="$sysctl_net_ipv6_conf_all_router_solicitations_value"
#
# If net.ipv6.conf.all.router_solicitations present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.all.router_solicitations = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.router_solicitations")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_router_solicitations_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 "^net.ipv6.conf.all.router_solicitations\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.router_solicitations\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.all.router_solicitations.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_router_solicitations
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.all.router_solicitations from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.all.router_solicitations
replace: '#net.ipv6.conf.all.router_solicitations'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_router_solicitations
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_all_router_solicitations_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_router_solicitations_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.router_solicitations is set
sysctl:
name: net.ipv6.conf.all.router_solicitations
value: '{{ sysctl_net_ipv6_conf_all_router_solicitations_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_all_router_solicitations
- unknown_severity
|
Configure Accepting Default Router in Router Advertisements on All IPv6 Interfaces By Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_ra_defrtr kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_ra_defrtr=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_ra_defrtr = 0 Rationale:An illicit router advertisement message could result in a man-in-the-middle attack. 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.ipv6.conf.default.accept_ra_defrtr from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_ra_defrtr.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.default.accept_ra_defrtr" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_default_accept_ra_defrtr_value='0'
#
# Set runtime for net.ipv6.conf.default.accept_ra_defrtr
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_ra_defrtr="$sysctl_net_ipv6_conf_default_accept_ra_defrtr_value"
#
# If net.ipv6.conf.default.accept_ra_defrtr present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.accept_ra_defrtr = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_ra_defrtr")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_ra_defrtr_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 "^net.ipv6.conf.default.accept_ra_defrtr\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_ra_defrtr\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.accept_ra_defrtr.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra_defrtr
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.default.accept_ra_defrtr from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.accept_ra_defrtr
replace: '#net.ipv6.conf.default.accept_ra_defrtr'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra_defrtr
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_ra_defrtr_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_ra_defrtr_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_ra_defrtr is set
sysctl:
name: net.ipv6.conf.default.accept_ra_defrtr
value: '{{ sysctl_net_ipv6_conf_default_accept_ra_defrtr_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra_defrtr
- unknown_severity
|
Configure Accepting Prefix Information in Router Advertisements on All IPv6 Interfaces By Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_ra_pinfo kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_ra_pinfo=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_ra_pinfo = 0 Rationale:An illicit router advertisement message could result in a man-in-the-middle attack. 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.ipv6.conf.default.accept_ra_pinfo from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_ra_pinfo.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.default.accept_ra_pinfo" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_default_accept_ra_pinfo_value='0'
#
# Set runtime for net.ipv6.conf.default.accept_ra_pinfo
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_ra_pinfo="$sysctl_net_ipv6_conf_default_accept_ra_pinfo_value"
#
# If net.ipv6.conf.default.accept_ra_pinfo present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.accept_ra_pinfo = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_ra_pinfo")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_ra_pinfo_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 "^net.ipv6.conf.default.accept_ra_pinfo\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_ra_pinfo\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.accept_ra_pinfo.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra_pinfo
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.default.accept_ra_pinfo from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.accept_ra_pinfo
replace: '#net.ipv6.conf.default.accept_ra_pinfo'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra_pinfo
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_ra_pinfo_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_ra_pinfo_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_ra_pinfo is set
sysctl:
name: net.ipv6.conf.default.accept_ra_pinfo
value: '{{ sysctl_net_ipv6_conf_default_accept_ra_pinfo_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra_pinfo
- unknown_severity
|
Configure Accepting Router Preference in Router Advertisements on All IPv6 Interfaces By Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_ra_rtr_pref kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_ra_rtr_pref=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_ra_rtr_pref = 0 Rationale:An illicit router advertisement message could result in a man-in-the-middle attack. 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.ipv6.conf.default.accept_ra_rtr_pref from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_ra_rtr_pref.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.default.accept_ra_rtr_pref" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_default_accept_ra_rtr_pref_value='0'
#
# Set runtime for net.ipv6.conf.default.accept_ra_rtr_pref
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_ra_rtr_pref="$sysctl_net_ipv6_conf_default_accept_ra_rtr_pref_value"
#
# If net.ipv6.conf.default.accept_ra_rtr_pref present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.accept_ra_rtr_pref = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_ra_rtr_pref")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_ra_rtr_pref_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 "^net.ipv6.conf.default.accept_ra_rtr_pref\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_ra_rtr_pref\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.accept_ra_rtr_pref.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra_rtr_pref
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.default.accept_ra_rtr_pref from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.accept_ra_rtr_pref
replace: '#net.ipv6.conf.default.accept_ra_rtr_pref'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra_rtr_pref
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_ra_rtr_pref_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_ra_rtr_pref_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_ra_rtr_pref is set
sysctl:
name: net.ipv6.conf.default.accept_ra_rtr_pref
value: '{{ sysctl_net_ipv6_conf_default_accept_ra_rtr_pref_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_accept_ra_rtr_pref
- unknown_severity
|
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_redirects = 0 Rationale:An illicit ICMP redirect message could result in a man-in-the-middle attack. References:
BP28(R22), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 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, 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 net.ipv6.conf.default.accept_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.default.accept_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_default_accept_redirects_value='0'
#
# Set runtime for net.ipv6.conf.default.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_redirects="$sysctl_net_ipv6_conf_default_accept_redirects_value"
#
# If net.ipv6.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.accept_redirects = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_redirects_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 "^net.ipv6.conf.default.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.accept_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_redirects
- name: Comment out any occurrences of net.ipv6.conf.default.accept_redirects from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.accept_redirects
replace: '#net.ipv6.conf.default.accept_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_redirects
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_redirects is set
sysctl:
name: net.ipv6.conf.default.accept_redirects
value: '{{ sysctl_net_ipv6_conf_default_accept_redirects_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_redirects
|
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv6 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router, which can
be used to bypass network security measures. This requirement applies only to the
forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and
the system is functioning as a router.
Accepting source-routed packets in the IPv6 protocol has few legitimate
uses. It should be disabled unless it is absolutely required. References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, 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.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.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4, Req-1.4.3, 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 net.ipv6.conf.default.accept_source_route from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_source_route.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.default.accept_source_route" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_default_accept_source_route_value='0'
#
# Set runtime for net.ipv6.conf.default.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_source_route="$sysctl_net_ipv6_conf_default_accept_source_route_value"
#
# If net.ipv6.conf.default.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.accept_source_route = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_source_route")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_source_route_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 "^net.ipv6.conf.default.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.accept_source_route.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
- name: Comment out any occurrences of net.ipv6.conf.default.accept_source_route from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.accept_source_route
replace: '#net.ipv6.conf.default.accept_source_route'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_source_route is set
sysctl:
name: net.ipv6.conf.default.accept_source_route
value: '{{ sysctl_net_ipv6_conf_default_accept_source_route_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
|
Configure Auto Configuration on All IPv6 Interfaces By Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.autoconf kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.autoconf=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.autoconf = 0 Rationale:An illicit router advertisement message could result in a man-in-the-middle attack. 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.ipv6.conf.default.autoconf from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.autoconf.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.default.autoconf" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_default_autoconf_value='0'
#
# Set runtime for net.ipv6.conf.default.autoconf
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.autoconf="$sysctl_net_ipv6_conf_default_autoconf_value"
#
# If net.ipv6.conf.default.autoconf present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.autoconf = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.autoconf")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_autoconf_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 "^net.ipv6.conf.default.autoconf\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.autoconf\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.autoconf.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_autoconf
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.default.autoconf from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.autoconf
replace: '#net.ipv6.conf.default.autoconf'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_autoconf
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_default_autoconf_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_autoconf_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.autoconf is set
sysctl:
name: net.ipv6.conf.default.autoconf
value: '{{ sysctl_net_ipv6_conf_default_autoconf_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_autoconf
- unknown_severity
|
Configure Maximum Number of Autoconfigured Addresses on All IPv6 Interfaces By Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.max_addresses kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.max_addresses=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.max_addresses = 1 Rationale:The number of global unicast IPv6 addresses for each interface should be limited exactly to the number of statically configured addresses. 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.ipv6.conf.default.max_addresses from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.max_addresses.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.default.max_addresses" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_default_max_addresses_value='1'
#
# Set runtime for net.ipv6.conf.default.max_addresses
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.max_addresses="$sysctl_net_ipv6_conf_default_max_addresses_value"
#
# If net.ipv6.conf.default.max_addresses present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.max_addresses = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.max_addresses")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_max_addresses_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 "^net.ipv6.conf.default.max_addresses\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.max_addresses\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.max_addresses.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_max_addresses
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.default.max_addresses from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.max_addresses
replace: '#net.ipv6.conf.default.max_addresses'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_max_addresses
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_default_max_addresses_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_max_addresses_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.max_addresses is set
sysctl:
name: net.ipv6.conf.default.max_addresses
value: '{{ sysctl_net_ipv6_conf_default_max_addresses_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_max_addresses
- unknown_severity
|
Configure Denying Router Solicitations on All IPv6 Interfaces By Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.router_solicitations kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.router_solicitations=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.router_solicitations = 0 Rationale:To prevent discovery of the system by other systems, router solicitation requests should be denied. 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.ipv6.conf.default.router_solicitations from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.router_solicitations.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.default.router_solicitations" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv6_conf_default_router_solicitations_value='0'
#
# Set runtime for net.ipv6.conf.default.router_solicitations
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.router_solicitations="$sysctl_net_ipv6_conf_default_router_solicitations_value"
#
# If net.ipv6.conf.default.router_solicitations present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.router_solicitations = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.router_solicitations")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_router_solicitations_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 "^net.ipv6.conf.default.router_solicitations\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.router_solicitations\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.router_solicitations.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_router_solicitations
- unknown_severity
- name: Comment out any occurrences of net.ipv6.conf.default.router_solicitations
from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.router_solicitations
replace: '#net.ipv6.conf.default.router_solicitations'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_router_solicitations
- unknown_severity
- name: XCCDF Value sysctl_net_ipv6_conf_default_router_solicitations_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_router_solicitations_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.router_solicitations is set
sysctl:
name: net.ipv6.conf.default.router_solicitations
value: '{{ sysctl_net_ipv6_conf_default_router_solicitations_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv6_conf_default_router_solicitations
- unknown_severity
|
Kernel Parameters Which Affect Networking
[ref]groupThe sysctl utility is used to set
parameters which affect the operation of the Linux kernel. Kernel parameters
which affect networking and have security implications are described here. |
contains 21 rules |
Network Related Kernel Runtime Parameters for Hosts and Routers
[ref]groupCertain kernel parameters should be set for systems which are
acting as either hosts or routers to improve the system's ability defend
against certain types of IPv4 protocol attacks. |
contains 18 rules |
Disable Accepting Packets Routed Between Local Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.accept_local kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.accept_local=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.accept_local = 0 Rationale:Configure net.ipv4.conf.all.accept_local=0 to consider as invalid the packets
received from outside whose source is the 127.0.0.0/8 address block.
In combination with suitable routing, this can be used to direct packets between two
local interfaces over the wire and have them accepted properly. 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.ipv4.conf.all.accept_local from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.accept_local.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.accept_local" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for net.ipv4.conf.all.accept_local
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.accept_local="0"
#
# If net.ipv4.conf.all.accept_local present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.all.accept_local = 0" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.accept_local")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# 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.ipv4.conf.all.accept_local\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.accept_local\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.accept_local.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_local
- name: Comment out any occurrences of net.ipv4.conf.all.accept_local from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.accept_local
replace: '#net.ipv4.conf.all.accept_local'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_local
- name: Ensure sysctl net.ipv4.conf.all.accept_local is set to 0
sysctl:
name: net.ipv4.conf.all.accept_local
value: '0'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_local
|
Disable Accepting ICMP Redirects for All IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.accept_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages modify the
host's route table and are unauthenticated. An illicit ICMP redirect
message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should be
disabled unless absolutely required." References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, 5.10.1.1, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000366, CCI-001503, CCI-001551, 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 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, OL07-00-040641, SV-221879r880654_rule 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.ipv4.conf.all.accept_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.accept_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.accept_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_all_accept_redirects_value='0'
#
# Set runtime for net.ipv4.conf.all.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.accept_redirects="$sysctl_net_ipv4_conf_all_accept_redirects_value"
#
# If net.ipv4.conf.all.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.accept_redirects = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.accept_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_accept_redirects_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 "^net.ipv4.conf.all.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.accept_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040641
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_redirects
- name: Comment out any occurrences of net.ipv4.conf.all.accept_redirects from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.accept_redirects
replace: '#net.ipv4.conf.all.accept_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040641
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_all_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.accept_redirects is set
sysctl:
name: net.ipv4.conf.all.accept_redirects
value: '{{ sysctl_net_ipv4_conf_all_accept_redirects_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040641
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_redirects
|
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router,
which can be used to bypass network security measures. This requirement
applies only to the forwarding of source-routerd traffic, such as when IPv4
forwarding is enabled and the system is functioning as a router.
Accepting source-routed packets in the IPv4 protocol has few legitimate
uses. It should be disabled unless it is absolutely required. References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 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, 4.3.4.3.2, 4.3.4.3.3, 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 2.2, 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 6.2, SR 7.1, SR 7.2, 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.12.1.3, A.12.5.1, A.12.6.2, 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.17.2.1, 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-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-040610, SV-221873r880636_rule 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.ipv4.conf.all.accept_source_route from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.accept_source_route.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.accept_source_route" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_all_accept_source_route_value='0'
#
# Set runtime for net.ipv4.conf.all.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.accept_source_route="$sysctl_net_ipv4_conf_all_accept_source_route_value"
#
# If net.ipv4.conf.all.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.accept_source_route = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.accept_source_route")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_accept_source_route_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 "^net.ipv4.conf.all.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.accept_source_route.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040610
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_source_route
- name: Comment out any occurrences of net.ipv4.conf.all.accept_source_route from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.accept_source_route
replace: '#net.ipv4.conf.all.accept_source_route'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040610
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_source_route
- name: XCCDF Value sysctl_net_ipv4_conf_all_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.accept_source_route is set
sysctl:
name: net.ipv4.conf.all.accept_source_route
value: '{{ sysctl_net_ipv4_conf_all_accept_source_route_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040610
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_source_route
|
Configure ARP filtering for All IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.arp_filter kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.arp_filter=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.arp_filter = 0 Warning:
This behaviour may cause problems to system on a high availability or load balancing configuration. Rationale:Prevents the Linux Kernel from handling the ARP table globally.
By default, the kernel may respond to an ARP request from a certain interface with information
from another interface. 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.ipv4.conf.all.arp_filter from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.arp_filter.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.arp_filter" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_all_arp_filter_value='0'
#
# Set runtime for net.ipv4.conf.all.arp_filter
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.arp_filter="$sysctl_net_ipv4_conf_all_arp_filter_value"
#
# If net.ipv4.conf.all.arp_filter present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.arp_filter = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.arp_filter")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_arp_filter_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 "^net.ipv4.conf.all.arp_filter\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.arp_filter\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.arp_filter.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_arp_filter
- name: Comment out any occurrences of net.ipv4.conf.all.arp_filter from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.arp_filter
replace: '#net.ipv4.conf.all.arp_filter'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_arp_filter
- name: XCCDF Value sysctl_net_ipv4_conf_all_arp_filter_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_arp_filter_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.arp_filter is set
sysctl:
name: net.ipv4.conf.all.arp_filter
value: '{{ sysctl_net_ipv4_conf_all_arp_filter_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_arp_filter
|
Configure Response Mode of ARP Requests for All IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.arp_ignore kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.arp_ignore=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.arp_ignore = 2 Warning:
The ARP response mode may impact behaviour of workloads and firewalls on the system. Rationale:Avoids ARP Flux on system that have more than one interface on the same subnet. 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.ipv4.conf.all.arp_ignore from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.arp_ignore.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.arp_ignore" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_all_arp_ignore_value='2'
#
# Set runtime for net.ipv4.conf.all.arp_ignore
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.arp_ignore="$sysctl_net_ipv4_conf_all_arp_ignore_value"
#
# If net.ipv4.conf.all.arp_ignore present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.arp_ignore = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.arp_ignore")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_arp_ignore_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 "^net.ipv4.conf.all.arp_ignore\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.arp_ignore\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.arp_ignore.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_arp_ignore
- name: Comment out any occurrences of net.ipv4.conf.all.arp_ignore from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.arp_ignore
replace: '#net.ipv4.conf.all.arp_ignore'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_arp_ignore
- name: XCCDF Value sysctl_net_ipv4_conf_all_arp_ignore_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_arp_ignore_value: !!str 2
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.arp_ignore is set
sysctl:
name: net.ipv4.conf.all.arp_ignore
value: '{{ sysctl_net_ipv4_conf_all_arp_ignore_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_arp_ignore
|
Prevent Routing External Traffic to Local Loopback on All IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.route_localnet kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.route_localnet=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.route_localnet = 0 Rationale:Refuse the routing of packets whose source or destination address is the local loopback.
This prohibits the use of network 127/8 for local routing purposes.
Enabling route_localnet can expose applications listening on localhost to external traffic. 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.ipv4.conf.all.route_localnet from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.route_localnet.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.route_localnet" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for net.ipv4.conf.all.route_localnet
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.route_localnet="0"
#
# If net.ipv4.conf.all.route_localnet present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.all.route_localnet = 0" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.route_localnet")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# 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.ipv4.conf.all.route_localnet\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.route_localnet\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.route_localnet.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_route_localnet
- name: Comment out any occurrences of net.ipv4.conf.all.route_localnet from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.route_localnet
replace: '#net.ipv4.conf.all.route_localnet'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_route_localnet
- name: Ensure sysctl net.ipv4.conf.all.route_localnet is set to 0
sysctl:
name: net.ipv4.conf.all.route_localnet
value: '0'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_route_localnet
|
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.rp_filter kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.rp_filter = 1 Rationale:Enabling reverse path filtering drops packets with source addresses
that should not have been able to be received on the interface they were
received on. It should not be used on systems which are routers for
complicated networks, but is helpful for end hosts and routers serving small
networks. References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.4.3.3, 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 6.2, SR 7.1, SR 7.2, 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.12.1.3, 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.17.2.1, 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), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, Req-1.4.3, SRG-OS-000480-GPOS-00227, OL07-00-040611, SV-221874r880639_rule 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.ipv4.conf.all.rp_filter from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.rp_filter.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.rp_filter" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_all_rp_filter_value='1'
#
# Set runtime for net.ipv4.conf.all.rp_filter
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.rp_filter="$sysctl_net_ipv4_conf_all_rp_filter_value"
#
# If net.ipv4.conf.all.rp_filter present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.rp_filter = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.rp_filter")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_rp_filter_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 "^net.ipv4.conf.all.rp_filter\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.rp_filter\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.rp_filter.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040611
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_rp_filter
- name: Comment out any occurrences of net.ipv4.conf.all.rp_filter from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.rp_filter
replace: '#net.ipv4.conf.all.rp_filter'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040611
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_rp_filter
- name: XCCDF Value sysctl_net_ipv4_conf_all_rp_filter_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_rp_filter_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.rp_filter is set
sysctl:
name: net.ipv4.conf.all.rp_filter
value: '{{ sysctl_net_ipv4_conf_all_rp_filter_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040611
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_rp_filter
|
Disable Kernel Parameter for Accepting Secure ICMP Redirects on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.secure_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.secure_redirects = 0 Rationale:Accepting "secure" ICMP redirects (from those gateways listed as
default gateways) has few legitimate uses. It should be disabled unless it is
absolutely required. References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-001503, CCI-001551, 4.2.3.4, 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, 4.3.4.3.2, 4.3.4.3.3, 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 2.2, 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 6.2, SR 7.1, SR 7.2, 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.12.1.3, A.12.5.1, A.12.6.2, 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.17.2.1, 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), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.4.3, 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 net.ipv4.conf.all.secure_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.secure_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.secure_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_all_secure_redirects_value='0'
#
# Set runtime for net.ipv4.conf.all.secure_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.secure_redirects="$sysctl_net_ipv4_conf_all_secure_redirects_value"
#
# If net.ipv4.conf.all.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.secure_redirects = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.secure_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_secure_redirects_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 "^net.ipv4.conf.all.secure_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.secure_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.secure_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_secure_redirects
- name: Comment out any occurrences of net.ipv4.conf.all.secure_redirects from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.secure_redirects
replace: '#net.ipv4.conf.all.secure_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_secure_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_all_secure_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_secure_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.secure_redirects is set
sysctl:
name: net.ipv4.conf.all.secure_redirects
value: '{{ sysctl_net_ipv4_conf_all_secure_redirects_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_secure_redirects
|
Configure Sending and Accepting Shared Media Redirects for All IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.shared_media kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.shared_media=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.shared_media = 0 Rationale:This setting should be aligned with net.ipv4.conf.all.secure_redirects because it overrides it.
If shared_media is enabled for an interface secure_redirects will be enabled too. 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.ipv4.conf.all.shared_media from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.shared_media.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.shared_media" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_all_shared_media_value='0'
#
# Set runtime for net.ipv4.conf.all.shared_media
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.shared_media="$sysctl_net_ipv4_conf_all_shared_media_value"
#
# If net.ipv4.conf.all.shared_media present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.shared_media = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.shared_media")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_shared_media_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 "^net.ipv4.conf.all.shared_media\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.shared_media\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.shared_media.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_shared_media
- name: Comment out any occurrences of net.ipv4.conf.all.shared_media from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.shared_media
replace: '#net.ipv4.conf.all.shared_media'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_shared_media
- name: XCCDF Value sysctl_net_ipv4_conf_all_shared_media_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_shared_media_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.shared_media is set
sysctl:
name: net.ipv4.conf.all.shared_media
value: '{{ sysctl_net_ipv4_conf_all_shared_media_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_shared_media
|
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.accept_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages modify the
host's route table and are unauthenticated. An illicit ICMP redirect
message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should
be disabled unless absolutely required. References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 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, 4.3.4.3.2, 4.3.4.3.3, 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 2.2, 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 6.2, SR 7.1, SR 7.2, 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.12.1.3, A.12.5.1, A.12.6.2, 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.17.2.1, 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), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.4.3, SRG-OS-000480-GPOS-00227, OL07-00-040640, SV-221878r880651_rule 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.ipv4.conf.default.accept_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.accept_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.default.accept_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_default_accept_redirects_value='0'
#
# Set runtime for net.ipv4.conf.default.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.accept_redirects="$sysctl_net_ipv4_conf_default_accept_redirects_value"
#
# If net.ipv4.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.accept_redirects = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.accept_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_accept_redirects_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 "^net.ipv4.conf.default.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.accept_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040640
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
- name: Comment out any occurrences of net.ipv4.conf.default.accept_redirects from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.accept_redirects
replace: '#net.ipv4.conf.default.accept_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040640
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_default_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.accept_redirects is set
sysctl:
name: net.ipv4.conf.default.accept_redirects
value: '{{ sysctl_net_ipv4_conf_default_accept_redirects_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040640
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
|
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv4 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router,
which can be used to bypass network security measures.
Accepting source-routed packets in the IPv4 protocol has few legitimate
uses. It should be disabled unless it is absolutely required, such as when
IPv4 forwarding is enabled and the system is legitimately functioning as a
router. References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 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, 4.3.4.3.2, 4.3.4.3.3, 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 2.2, 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 6.2, SR 7.1, SR 7.2, 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.12.1.3, A.12.5.1, A.12.6.2, 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.17.2.1, 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-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-040620, SV-221876r880645_rule 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.ipv4.conf.default.accept_source_route from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.accept_source_route.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.default.accept_source_route" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_default_accept_source_route_value='0'
#
# Set runtime for net.ipv4.conf.default.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.accept_source_route="$sysctl_net_ipv4_conf_default_accept_source_route_value"
#
# If net.ipv4.conf.default.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.accept_source_route = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.accept_source_route")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_accept_source_route_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 "^net.ipv4.conf.default.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.accept_source_route.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040620
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_source_route
- name: Comment out any occurrences of net.ipv4.conf.default.accept_source_route from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.accept_source_route
replace: '#net.ipv4.conf.default.accept_source_route'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040620
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_source_route
- name: XCCDF Value sysctl_net_ipv4_conf_default_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.accept_source_route is set
sysctl:
name: net.ipv4.conf.default.accept_source_route
value: '{{ sysctl_net_ipv4_conf_default_accept_source_route_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040620
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_source_route
|
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.rp_filter kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.rp_filter = 1 Rationale:Enabling reverse path filtering drops packets with source addresses
that should not have been able to be received on the interface they were
received on. It should not be used on systems which are routers for
complicated networks, but is helpful for end hosts and routers serving small
networks. References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, 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 6.2, SR 7.1, SR 7.2, 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.12.1.3, 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.17.2.1, 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), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-040612, SV-221875r880642_rule 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.ipv4.conf.default.rp_filter from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.rp_filter.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.default.rp_filter" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_default_rp_filter_value='1'
#
# Set runtime for net.ipv4.conf.default.rp_filter
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.rp_filter="$sysctl_net_ipv4_conf_default_rp_filter_value"
#
# If net.ipv4.conf.default.rp_filter present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.rp_filter = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.rp_filter")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_rp_filter_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 "^net.ipv4.conf.default.rp_filter\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.rp_filter\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.rp_filter.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040612
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_rp_filter
- name: Comment out any occurrences of net.ipv4.conf.default.rp_filter from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.rp_filter
replace: '#net.ipv4.conf.default.rp_filter'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040612
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_rp_filter
- name: XCCDF Value sysctl_net_ipv4_conf_default_rp_filter_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_rp_filter_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.rp_filter is set
sysctl:
name: net.ipv4.conf.default.rp_filter
value: '{{ sysctl_net_ipv4_conf_default_rp_filter_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040612
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_rp_filter
|
Configure Kernel Parameter for Accepting Secure Redirects By Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.secure_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.secure_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.secure_redirects = 0 Rationale:Accepting "secure" ICMP redirects (from those gateways listed as
default gateways) has few legitimate uses. It should be disabled unless it is
absolutely required. References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-001551, 4.2.3.4, 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, 4.3.4.3.2, 4.3.4.3.3, 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 2.2, 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 6.2, SR 7.1, SR 7.2, 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.12.1.3, A.12.5.1, A.12.6.2, 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.17.2.1, 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-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, 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 net.ipv4.conf.default.secure_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.secure_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.default.secure_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_default_secure_redirects_value='0'
#
# Set runtime for net.ipv4.conf.default.secure_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.secure_redirects="$sysctl_net_ipv4_conf_default_secure_redirects_value"
#
# If net.ipv4.conf.default.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.secure_redirects = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.secure_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_secure_redirects_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 "^net.ipv4.conf.default.secure_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.secure_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.secure_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_secure_redirects
- name: Comment out any occurrences of net.ipv4.conf.default.secure_redirects from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.secure_redirects
replace: '#net.ipv4.conf.default.secure_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_secure_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_default_secure_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_secure_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.secure_redirects is set
sysctl:
name: net.ipv4.conf.default.secure_redirects
value: '{{ sysctl_net_ipv4_conf_default_secure_redirects_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_secure_redirects
|
Configure Sending and Accepting Shared Media Redirects by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.shared_media kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.shared_media=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.shared_media = 0 Rationale:This setting should be aligned with net.ipv4.conf.default.secure_redirects because it overrides it.
If shared_media is enabled for an interface secure_redirects will be enabled too. 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.ipv4.conf.default.shared_media from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.shared_media.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.default.shared_media" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_conf_default_shared_media_value='0'
#
# Set runtime for net.ipv4.conf.default.shared_media
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.shared_media="$sysctl_net_ipv4_conf_default_shared_media_value"
#
# If net.ipv4.conf.default.shared_media present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.shared_media = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.shared_media")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_shared_media_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 "^net.ipv4.conf.default.shared_media\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.shared_media\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.shared_media.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_shared_media
- name: Comment out any occurrences of net.ipv4.conf.default.shared_media from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.shared_media
replace: '#net.ipv4.conf.default.shared_media'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_shared_media
- name: XCCDF Value sysctl_net_ipv4_conf_default_shared_media_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_shared_media_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.shared_media is set
sysctl:
name: net.ipv4.conf.default.shared_media
value: '{{ sysctl_net_ipv4_conf_default_shared_media_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_shared_media
|
Enable Kernel Parameter to Ignore Bogus ICMP Error Responses on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.icmp_ignore_bogus_error_responses kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.icmp_ignore_bogus_error_responses = 1 Rationale:Ignoring bogus ICMP error responses reduces
log size, although some activity would not be logged. References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, 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 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, Req-1.4.3, 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 net.ipv4.icmp_ignore_bogus_error_responses from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.icmp_ignore_bogus_error_responses.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.icmp_ignore_bogus_error_responses" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value='1'
#
# Set runtime for net.ipv4.icmp_ignore_bogus_error_responses
#
/sbin/sysctl -q -n -w net.ipv4.icmp_ignore_bogus_error_responses="$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value"
#
# If net.ipv4.icmp_ignore_bogus_error_responses present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.icmp_ignore_bogus_error_responses = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.icmp_ignore_bogus_error_responses")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_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 "^net.ipv4.icmp_ignore_bogus_error_responses\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.icmp_ignore_bogus_error_responses\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_icmp_ignore_bogus_error_responses
- unknown_severity
- name: Comment out any occurrences of net.ipv4.icmp_ignore_bogus_error_responses
from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses
replace: '#net.ipv4.icmp_ignore_bogus_error_responses'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_icmp_ignore_bogus_error_responses
- unknown_severity
- name: XCCDF Value sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value # promote to variable
set_fact:
sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.icmp_ignore_bogus_error_responses is set
sysctl:
name: net.ipv4.icmp_ignore_bogus_error_responses
value: '{{ sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_icmp_ignore_bogus_error_responses
- unknown_severity
|
Set Kernel Parameter to Increase Local Port Range
[ref]ruleTo set the runtime status of the net.ipv4.ip_local_port_range kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.ip_local_port_range=32768 65535
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.ip_local_port_range = 32768 65535 Rationale:This setting defines the local port range that is used by TCP and UDP to
choose the local port. The first number is the first, the second the last
local port number. 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.ipv4.ip_local_port_range from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.ip_local_port_range.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.ip_local_port_range" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for net.ipv4.ip_local_port_range
#
/sbin/sysctl -q -n -w net.ipv4.ip_local_port_range="32768 65535"
#
# If net.ipv4.ip_local_port_range present in /etc/sysctl.conf, change value to "32768 65535"
# else, add "net.ipv4.ip_local_port_range = 32768 65535" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.ip_local_port_range")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "32768 65535"
# 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.ipv4.ip_local_port_range\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.ip_local_port_range\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.ip_local_port_range.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_local_port_range
- name: Comment out any occurrences of net.ipv4.ip_local_port_range from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.ip_local_port_range
replace: '#net.ipv4.ip_local_port_range'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_local_port_range
- name: Ensure sysctl net.ipv4.ip_local_port_range is set to 32768 65535
sysctl:
name: net.ipv4.ip_local_port_range
value: 32768 65535
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_local_port_range
|
Enable Kernel Parameter to Use TCP RFC 1337 on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.tcp_rfc1337 kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.tcp_rfc1337=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.tcp_rfc1337 = 1 Rationale:Enable TCP behavior conformant with RFC 1337. When disabled, if a RST is
received in TIME_WAIT state, we close the socket immediately without waiting
for the end of the TIME_WAIT period. 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.ipv4.tcp_rfc1337 from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.tcp_rfc1337.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.tcp_rfc1337" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_tcp_rfc1337_value='1'
#
# Set runtime for net.ipv4.tcp_rfc1337
#
/sbin/sysctl -q -n -w net.ipv4.tcp_rfc1337="$sysctl_net_ipv4_tcp_rfc1337_value"
#
# If net.ipv4.tcp_rfc1337 present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.tcp_rfc1337 = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.tcp_rfc1337")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_tcp_rfc1337_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 "^net.ipv4.tcp_rfc1337\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.tcp_rfc1337\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.tcp_rfc1337.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_rfc1337
- name: Comment out any occurrences of net.ipv4.tcp_rfc1337 from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.tcp_rfc1337
replace: '#net.ipv4.tcp_rfc1337'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_rfc1337
- name: XCCDF Value sysctl_net_ipv4_tcp_rfc1337_value # promote to variable
set_fact:
sysctl_net_ipv4_tcp_rfc1337_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.tcp_rfc1337 is set
sysctl:
name: net.ipv4.tcp_rfc1337
value: '{{ sysctl_net_ipv4_tcp_rfc1337_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_rfc1337
|
Enable Kernel Parameter to Use TCP Syncookies on Network Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.tcp_syncookies kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.tcp_syncookies=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.tcp_syncookies = 1 Rationale:A TCP SYN flood attack can cause a denial of service by filling a
system's TCP connection table with connections in the SYN_RCVD state.
Syncookies can be used to track a connection when a subsequent ACK is received,
verifying the initiator is attempting a valid connection and is not a flood
source. This feature is activated when a flood condition is detected, and
enables the system to continue servicing valid connection requests. References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, CCI-001095, 4.2.3.4, 4.3.3.4, 4.4.3.3, 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 6.2, SR 7.1, SR 7.2, 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.12.1.3, 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.17.2.1, 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), SC-5(1), SC-5(2), SC-5(3)(a), CM-6(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, Req-1.4.1, SRG-OS-000480-GPOS-00227, SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00071 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.ipv4.tcp_syncookies from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.tcp_syncookies.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.tcp_syncookies" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_net_ipv4_tcp_syncookies_value='1'
#
# Set runtime for net.ipv4.tcp_syncookies
#
/sbin/sysctl -q -n -w net.ipv4.tcp_syncookies="$sysctl_net_ipv4_tcp_syncookies_value"
#
# If net.ipv4.tcp_syncookies present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.tcp_syncookies = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.tcp_syncookies")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_tcp_syncookies_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 "^net.ipv4.tcp_syncookies\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.tcp_syncookies\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.tcp_syncookies.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- PCI-DSS-Req-1.4.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
- name: Comment out any occurrences of net.ipv4.tcp_syncookies from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.tcp_syncookies
replace: '#net.ipv4.tcp_syncookies'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- PCI-DSS-Req-1.4.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
- name: XCCDF Value sysctl_net_ipv4_tcp_syncookies_value # promote to variable
set_fact:
sysctl_net_ipv4_tcp_syncookies_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.tcp_syncookies is set
sysctl:
name: net.ipv4.tcp_syncookies
value: '{{ sysctl_net_ipv4_tcp_syncookies_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- PCI-DSS-Req-1.4.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
|
Network Parameters for Hosts Only
[ref]groupIf the system is not going to be used as a router, then setting certain
kernel parameters ensure that the host will not perform routing
of network traffic. |
contains 3 rules |
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.send_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.send_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages contain information
from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers. References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 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, 4.3.4.3.2, 4.3.4.3.3, 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 2.2, 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 6.2, SR 7.1, SR 7.2, 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.12.1.3, A.12.5.1, A.12.6.2, 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.17.2.1, 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-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, 1.4.2, SRG-OS-000480-GPOS-00227, OL07-00-040660, SV-221881r880660_rule 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.ipv4.conf.all.send_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.send_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.send_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for net.ipv4.conf.all.send_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.send_redirects="0"
#
# If net.ipv4.conf.all.send_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.all.send_redirects = 0" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.send_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# 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.ipv4.conf.all.send_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.send_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.send_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040660
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
- name: Comment out any occurrences of net.ipv4.conf.all.send_redirects from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.send_redirects
replace: '#net.ipv4.conf.all.send_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040660
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
- name: Ensure sysctl net.ipv4.conf.all.send_redirects is set to 0
sysctl:
name: net.ipv4.conf.all.send_redirects
value: '0'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040660
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
|
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.send_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.send_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages contain information
from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers. References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 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, 4.3.4.3.2, 4.3.4.3.3, 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 2.2, 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 6.2, SR 7.1, SR 7.2, 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.12.1.3, A.12.5.1, A.12.6.2, 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.17.2.1, 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-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-040650, SV-221880r880657_rule 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.ipv4.conf.default.send_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.send_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.default.send_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for net.ipv4.conf.default.send_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.send_redirects="0"
#
# If net.ipv4.conf.default.send_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.default.send_redirects = 0" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.send_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# 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.ipv4.conf.default.send_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.send_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.send_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040650
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
- name: Comment out any occurrences of net.ipv4.conf.default.send_redirects from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.send_redirects
replace: '#net.ipv4.conf.default.send_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040650
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
- name: Ensure sysctl net.ipv4.conf.default.send_redirects is set to 0
sysctl:
name: net.ipv4.conf.default.send_redirects
value: '0'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.10.1.1
- DISA-STIG-OL07-00-040650
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
|
Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.ip_forward kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.ip_forward=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.ip_forward = 0 Warning:
Certain technologies such as virtual machines, containers, etc. rely on IPv4 forwarding to enable and use networking.
Disabling IPv4 forwarding would cause those technologies to stop working. Therefore, this rule should not be used in
profiles or benchmarks that target usage of IPv4 forwarding. Rationale:Routing protocol daemons are typically used on routers to exchange
network topology information with other routers. If this capability is used when
not required, system network information may be unnecessarily transmitted across
the network. References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, 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 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, 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.17.2.1, A.9.1.2, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.3.1, Req-1.3.2, 1.4.2, SRG-OS-000480-GPOS-00227, OL07-00-040740, SV-221889r880663_rule 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.ipv4.ip_forward from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.ip_forward.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.ip_forward" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for net.ipv4.ip_forward
#
/sbin/sysctl -q -n -w net.ipv4.ip_forward="0"
#
# If net.ipv4.ip_forward present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.ip_forward = 0" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.ip_forward")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# 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.ipv4.ip_forward\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.ip_forward\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*net.ipv4.ip_forward.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040740
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.3.1
- PCI-DSS-Req-1.3.2
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
- name: Comment out any occurrences of net.ipv4.ip_forward from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.ip_forward
replace: '#net.ipv4.ip_forward'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040740
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.3.1
- PCI-DSS-Req-1.3.2
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
- name: Ensure sysctl net.ipv4.ip_forward is set to 0
sysctl:
name: net.ipv4.ip_forward
value: '0'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040740
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.3.1
- PCI-DSS-Req-1.3.2
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
|
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 Oracle Linux 7
installations:
$ mount -t xfs | awk '{print $3}'
For any systems that use a different
local filesystem type, modify this command as appropriate. |
contains 44 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 15 rules |
Verify Permissions on Files with Local Account Information and Credentials
[ref]groupThe default restrictive permissions for files which act as
important security databases such as passwd , shadow ,
group , and gshadow files must be maintained. Many utilities
need read access to the passwd file in order to function properly, but
read access to the shadow file allows malicious attacks against system
passwords, and should never be enabled. |
contains 6 rules |
Verify User Who Owns gshadow File
[ref]rule To properly set the owner of /etc/gshadow , run the command: $ sudo chown root /etc/gshadow Rationale:The /etc/gshadow file contains group password hashes. Protection of this file
is critical for system security. References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 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-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/gshadow
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/gshadow
stat:
path: /etc/gshadow
register: file_exists
tags:
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/gshadow
file:
path: /etc/gshadow
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Verify User Who Owns shadow File
[ref]rule To properly set the owner of /etc/shadow , run the command: $ sudo chown root /etc/shadow Rationale:The /etc/shadow file contains the list of local
system accounts and stores password hashes. Protection of this file is
critical for system security. Failure to give ownership of this file
to root provides the designated owner with access to sensitive information
which could weaken the system security posture. References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 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, Req-8.7.c, 7.2.6, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/shadow
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow
stat:
path: /etc/shadow
register: file_exists
tags:
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-7.2.6
- configure_strategy
- file_owner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/shadow
file:
path: /etc/shadow
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-7.2.6
- configure_strategy
- file_owner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Verify Permissions on group File
[ref]rule
To properly set the permissions of /etc/passwd , run the command:
$ sudo chmod 0644 /etc/passwd Rationale:The /etc/group file contains information regarding groups that are configured
on the system. Protection of this file is important for system security. References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 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, Req-8.7.c, 7.2.6, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/group
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group
stat:
path: /etc/group
register: file_exists
tags:
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-7.2.6
- configure_strategy
- file_permissions_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/group
file:
path: /etc/group
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-7.2.6
- configure_strategy
- file_permissions_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Verify Permissions on gshadow File
[ref]rule
To properly set the permissions of /etc/gshadow , run the command:
$ sudo chmod 0000 /etc/gshadow Rationale:The /etc/gshadow file contains group password hashes. Protection of this file
is critical for system security. References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 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-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xwrs,g-xwrs,o-xwrt /etc/gshadow
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/gshadow
stat:
path: /etc/gshadow
register: file_exists
tags:
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xwrs,g-xwrs,o-xwrt on /etc/gshadow
file:
path: /etc/gshadow
mode: u-xwrs,g-xwrs,o-xwrt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_etc_gshadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Verify Permissions on passwd File
[ref]rule
To properly set the permissions of /etc/passwd , run the command:
$ sudo chmod 0644 /etc/passwd Rationale:If the /etc/passwd file is writable by a group-owner or the
world the risk of its compromise is increased. The file contains the list of
accounts on the system and associated information, and protection of this file
is critical for system security. References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 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, Req-8.7.c, 7.2.6, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/passwd
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd
stat:
path: /etc/passwd
register: file_exists
tags:
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-7.2.6
- configure_strategy
- file_permissions_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/passwd
file:
path: /etc/passwd
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-7.2.6
- configure_strategy
- file_permissions_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Verify Permissions on shadow File
[ref]rule
To properly set the permissions of /etc/shadow , run the command:
$ sudo chmod 0000 /etc/shadow Rationale:The /etc/shadow file contains the list of local
system accounts and stores password hashes. Protection of this file is
critical for system security. Failure to give ownership of this file
to root provides the designated owner with access to sensitive information
which could weaken the system security posture. References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 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, Req-8.7.c, 7.2.6, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xwrs,g-xwrs,o-xwrt /etc/shadow
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow
stat:
path: /etc/shadow
register: file_exists
tags:
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-7.2.6
- configure_strategy
- file_permissions_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xwrs,g-xwrs,o-xwrt on /etc/shadow
file:
path: /etc/shadow
mode: u-xwrs,g-xwrs,o-xwrt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-7.2.6
- configure_strategy
- file_permissions_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Ensure All World-Writable Directories Are Owned by root user
[ref]ruleAll directories in local partitions which are world-writable should be owned
by root. If any world-writable directories are not owned by root, this
should be investigated. Following this, the files should be deleted or
assigned to root user. Rationale:Allowing a user account to own a world-writable directory is
undesirable because it allows the owner of that directory to remove
or replace any files that may be placed in the directory by other
users. Remediation Shell script: (show)
find / -not -fstype afs -not -fstype ceph -not -fstype cifs -not -fstype smb3 -not -fstype smbfs -not -fstype sshfs -not -fstype ncpfs -not -fstype ncp -not -fstype nfs -not -fstype nfs4 -not -fstype gfs -not -fstype gfs2 -not -fstype glusterfs -not -fstype gpfs -not -fstype pvfs2 -not -fstype ocfs2 -not -fstype lustre -not -fstype davfs -not -fstype fuse.sshfs -type d -perm -0002 -uid +0 -exec chown root {} \;
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Configure excluded (non local) file systems
set_fact:
excluded_fstypes:
- afs
- ceph
- cifs
- smb3
- smbfs
- sshfs
- ncpfs
- ncp
- nfs
- nfs4
- gfs
- gfs2
- glusterfs
- gpfs
- pvfs2
- ocfs2
- lustre
- davfs
- fuse.sshfs
tags:
- dir_perms_world_writable_root_owned
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Create empty list of excluded paths
set_fact:
excluded_paths: []
tags:
- dir_perms_world_writable_root_owned
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Detect nonlocal file systems and add them to excluded paths
set_fact:
excluded_paths: '{{ excluded_paths | union([item.mount]) }}'
loop: '{{ ansible_mounts }}'
when: item.fstype in excluded_fstypes
tags:
- dir_perms_world_writable_root_owned
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Find all directories excluding non-local partitions
find:
paths: /
excludes: excluded_paths
file_type: directory
hidden: true
recurse: true
register: found_dirs
tags:
- dir_perms_world_writable_root_owned
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Create list of world writable directories
set_fact:
world_writable_dirs: '{{ found_dirs.files | selectattr(''woth'') | list }}'
tags:
- dir_perms_world_writable_root_owned
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Change owner to root on directories which are world writable
file:
path: '{{ item.path }}'
owner: root
loop: '{{ world_writable_dirs }}'
ignore_errors: true
tags:
- dir_perms_world_writable_root_owned
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
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. 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 '$6' find '$6' -xdev -type d \
\( -perm -0002 -a ! -perm -1000 \) 2>/dev/null \
-exec chmod a+t {} +
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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:
- 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:
- 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. 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. 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. 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, 2.2.6 Remediation Shell script: (show)
find / -xdev -type f -perm -002 -exec chmod o-w {} \;
|
Ensure All Files Are Owned by a Group
[ref]ruleIf any files are not owned by a group, then the
cause of their lack of group-ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate group. The following command will discover and print
any files on local partitions which do not belong to a valid group:
$ df --local -P | awk '{if (NR!=1) print $6}' | sudo xargs -I '{}' find '{}' -xdev -nogroup
To search all filesystems on a system including network mounted
filesystems the following command can be run manually for each partition:
$ sudo find PARTITION -xdev -nogroup Warning:
This rule only considers local groups.
If you have your groups defined outside /etc/group , the rule won't consider those. Rationale:Unowned files do not directly imply a security problem, but they are generally
a sign that something is amiss. They may
be caused by an intruder, by incorrect software installation or
draft software removal, or by failure to remove all files belonging
to a deleted account. The files should be repaired so they
will not cause problems when accounts are created in the future,
and the cause should be discovered and addressed. References:
BP28(R55), 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, CCI-000366, CCI-002165, 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, CM-6(a), AC-6(1), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, 2.2.6, SRG-OS-000480-GPOS-00227, OL07-00-020330, SV-221725r603260_rule |
Ensure All Files Are Owned by a User
[ref]ruleIf any files are not owned by a user, then the
cause of their lack of ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate user. The following command will discover and print
any files on local partitions which do not belong to a valid user:
$ df --local -P | awk {'if (NR!=1) print $6'} | sudo xargs -I '{}' find '{}' -xdev -nouser
To search all filesystems on a system including network mounted
filesystems the following command can be run manually for each partition:
$ sudo find PARTITION -xdev -nouser Warning:
For this rule to evaluate centralized user accounts, getent must be working properly
so that running the command getent passwd returns a list of all users in your organization.
If using the System Security Services Daemon (SSSD), enumerate = true must be configured
in your organization's domain to return a complete list of users Warning:
Enabling this rule will result in slower scan times depending on the size of your organization
and number of centralized users. Rationale:Unowned files do not directly imply a security problem, but they are generally
a sign that something is amiss. They may
be caused by an intruder, by incorrect software installation or
draft software removal, or by failure to remove all files belonging
to a deleted account. The files should be repaired so they
will not cause problems when accounts are created in the future,
and the cause should be discovered and addressed. References:
BP28(R55), 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, CCI-000366, CCI-002165, 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, CM-6(a), AC-6(1), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, 2.2.6, SRG-OS-000480-GPOS-00227, OL07-00-020320, SV-221724r603260_rule |
Enable Kernel Parameter to Enforce DAC on Hardlinks
[ref]ruleTo set the runtime status of the fs.protected_hardlinks kernel parameter, run the following command: $ sudo sysctl -w fs.protected_hardlinks=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : fs.protected_hardlinks = 1 Rationale:By enabling this kernel parameter, users can no longer create soft or hard links to
files which they do not own. Disallowing such hardlinks mitigate vulnerabilities
based on insecure file system accessed by privileged programs, avoiding an
exploitation vector exploiting unsafe use of open() or creat() . References:
BP28(R23), CCI-002165, 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), SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000324-GPOS-00125 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 fs.protected_hardlinks from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*fs.protected_hardlinks.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "fs.protected_hardlinks" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for fs.protected_hardlinks
#
/sbin/sysctl -q -n -w fs.protected_hardlinks="1"
#
# If fs.protected_hardlinks present in /etc/sysctl.conf, change value to "1"
# else, add "fs.protected_hardlinks = 1" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^fs.protected_hardlinks")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$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 "^fs.protected_hardlinks\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^fs.protected_hardlinks\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*fs.protected_hardlinks.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_protected_hardlinks
- name: Comment out any occurrences of fs.protected_hardlinks from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*fs.protected_hardlinks
replace: '#fs.protected_hardlinks'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_protected_hardlinks
- name: Ensure sysctl fs.protected_hardlinks is set to 1
sysctl:
name: fs.protected_hardlinks
value: '1'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_protected_hardlinks
|
Enable Kernel Parameter to Enforce DAC on Symlinks
[ref]ruleTo set the runtime status of the fs.protected_symlinks kernel parameter, run the following command: $ sudo sysctl -w fs.protected_symlinks=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : fs.protected_symlinks = 1 Rationale:By enabling this kernel parameter, symbolic links are permitted to be followed
only when outside a sticky world-writable directory, or when the UID of the
link and follower match, or when the directory owner matches the symlink's owner.
Disallowing such symlinks helps mitigate vulnerabilities based on insecure file system
accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of
open() or creat() . References:
BP28(R23), CCI-002165, 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), SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000324-GPOS-00125 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 fs.protected_symlinks from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*fs.protected_symlinks.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "fs.protected_symlinks" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for fs.protected_symlinks
#
/sbin/sysctl -q -n -w fs.protected_symlinks="1"
#
# If fs.protected_symlinks present in /etc/sysctl.conf, change value to "1"
# else, add "fs.protected_symlinks = 1" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^fs.protected_symlinks")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$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 "^fs.protected_symlinks\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^fs.protected_symlinks\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*fs.protected_symlinks.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_protected_symlinks
- name: Comment out any occurrences of fs.protected_symlinks from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*fs.protected_symlinks
replace: '#fs.protected_symlinks'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_protected_symlinks
- name: Ensure sysctl fs.protected_symlinks is set to 1
sysctl:
name: fs.protected_symlinks
value: '1'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_protected_symlinks
|
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 15 rules |
Add noexec Option to /boot
[ref]ruleThe noexec mount option can be used to prevent binaries from being
executed out of /boot .
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/boot . Rationale:The /boot partition contains the kernel and the bootloader. No
binaries should be executed from this partition after the booting process
finishes. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /boot --mountoptions="noexec"
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="$(printf "[[:space:]]%s[[:space:]]" "/boot")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/boot' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /boot in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /boot)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /boot 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 "noexec"; 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 "/boot"; then
if mountpoint -q "/boot"; then
mount -o remount --target "/boot"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add noexec Option to /boot: Check information associated to mountpoint'
command: findmnt --fstab '/boot'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_boot_noexec
- no_reboot_needed
- name: 'Add noexec Option to /boot: 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:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_boot_noexec
- no_reboot_needed
- name: 'Add noexec Option to /boot: If /boot not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /boot
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_boot_noexec
- no_reboot_needed
- name: 'Add noexec Option to /boot: Make sure noexec option is part of the to /boot
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:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_boot_noexec
- no_reboot_needed
- name: 'Add noexec Option to /boot: Ensure /boot is mounted with noexec option'
mount:
path: /boot
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 ("--fstab"
| length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_boot_noexec
- no_reboot_needed
|
Add nosuid Option to /boot
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /boot . The SUID and SGID permissions
should not be required on the boot partition.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/boot . Rationale:The presence of SUID and SGID executables should be tightly controlled. Users
should not be able to execute SUID or SGID binaries from boot partitions. References:
BP28(R12), CCI-000366, 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, SRG-OS-000480-GPOS-00227 Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /boot --mountoptions="nosuid"
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="$(printf "[[:space:]]%s[[:space:]]" "/boot")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/boot' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /boot in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /boot)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /boot 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 "nosuid"; 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 "/boot"; then
if mountpoint -q "/boot"; then
mount -o remount --target "/boot"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /boot: Check information associated to mountpoint'
command: findmnt --fstab '/boot'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- 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_boot_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /boot: 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:
- 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_boot_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /boot: If /boot not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /boot
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- 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_boot_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /boot: Make sure nosuid option is part of the to /boot
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:
- 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_boot_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /boot: Ensure /boot is mounted with nosuid option'
mount:
path: /boot
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 ("--fstab"
| length == 0)
tags:
- 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_boot_nosuid
- no_reboot_needed
|
Add noexec Option to /home
[ref]ruleThe noexec mount option can be used to prevent binaries from being
executed out of /home .
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/home . Warning:
OVAL looks for partitions whose mount point is a substring of any interactive user's home
directory and validates that noexec option is there. Because of this, there could be false
negatives when several partitions share a base substring. For example, if there is a home
directory in /var/tmp/user1 and there are partitions mounted in /var and
/var/tmp . The noexec option is only expected in /var/tmp , but OVAL will
check both.
Bash remediation uses the df command to find out the partition where the home
directory is mounted. However, if the directory doesn't exist the remediation won't be
applied. Rationale:The /home directory contains data of individual users. Binaries in
this directory should not be considered as trusted and users should not be
able to execute them. 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:]]" $1)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " $1 defaults,${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 "$mount_point_match_regexp" /etc/fstab | grep "noexec"; then
previous_mount_opts=$(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 "$1"; then
if mountpoint -q "$1"; then
mount -o remount --target "$1"
fi
fi
}
readarray -t home_directories < \
<(awk -F':' '{if ($3>=1000 && $3!= 65534) print $6}' /etc/passwd )
for home_directory in "${home_directories[@]}"
do
if [ -d $home_directory ]; then
fstab_mount_point=$(df $home_directory | awk '/^\/dev/ {print $6}')
if ! grep -qP "^/$|^/lib$|^/opt$|^/usr$|^/bin$|^/sbin$|^/boot$|^/dev$|^/proc$" <<< $fstab_mount_point
then
perform_remediation "$fstab_mount_point"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Add nosuid Option to /home
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /home . The SUID and SGID permissions
should not be required in these user data directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/home . Warning:
OVAL looks for partitions whose mount point is a substring of any interactive user's home
directory and validates that noexec option is there. Because of this, there could be false
negatives when several partitions share a base substring. For example, if there is a home
directory in /var/tmp/user1 and there are partitions mounted in /var and
/var/tmp . The noexec option is only expected in /var/tmp , but OVAL will
check both.
Bash remediation uses the df command to find out the partition where the home
directory is mounted. However, if the directory doesn't exist the remediation won't be
applied. Rationale:The presence of SUID and SGID executables should be tightly controlled. Users
should not be able to execute SUID or SGID binaries from user home directory partitions. References:
BP28(R12), 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-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.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, SRG-OS-000480-GPOS-00227, OL07-00-021000, SV-221741r603801_rule 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:]]" $1)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " $1 defaults,${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 "$mount_point_match_regexp" /etc/fstab | grep "nosuid"; then
previous_mount_opts=$(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 "$1"; then
if mountpoint -q "$1"; then
mount -o remount --target "$1"
fi
fi
}
readarray -t home_directories < \
<(awk -F':' '{if ($3>=1000 && $3!= 65534) print $6}' /etc/passwd )
for home_directory in "${home_directories[@]}"
do
if [ -d $home_directory ]; then
fstab_mount_point=$(df $home_directory | awk '/^\/dev/ {print $6}')
if ! grep -qP "^/$|^/lib$|^/opt$|^/usr$|^/bin$|^/sbin$|^/boot$|^/dev$|^/proc$" <<< $fstab_mount_point
then
perform_remediation "$fstab_mount_point"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Add nodev Option to Non-Root Local Partitions
[ref]ruleThe nodev mount option prevents files from being interpreted as
character or block devices. Legitimate character and block devices should
exist only in the /dev directory on the root partition or within
chroot jails built for system services.
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
any non-root local partitions. Rationale:The nodev mount option prevents files from being
interpreted as character or block devices. The only legitimate location
for device files is the /dev directory located on the root partition.
The only exception to this is chroot jails, for which it is not advised
to set nodev on these filesystems. References:
BP28(R12), 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, 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-3, SRG-OS-000368-GPOS-00154, SRG-OS-000480-GPOS-00227 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
MOUNT_OPTION="nodev"
# Create array of local non-root partitions
readarray -t partitions_records < <(findmnt --mtab --raw --evaluate | grep "^/\w" | grep "\s/dev/\w")
# Create array of polyinstantiated directories, in case one of them is found in mtab
readarray -t polyinstantiated_dirs < \
<(grep -oP "^\s*[^#\s]+\s+\S+" /etc/security/namespace.conf | grep -oP "(?<=\s)\S+?(?=/?\$)")
for partition_record in "${partitions_records[@]}"; do
# Get all important information for fstab
mount_point="$(echo ${partition_record} | cut -d " " -f1)"
device="$(echo ${partition_record} | cut -d " " -f2)"
device_type="$(echo ${partition_record} | cut -d " " -f3)"
if ! printf '%s\0' "${polyinstantiated_dirs[@]}" | grep -qxzF "$mount_point"; then
# device and device_type will be used only in case when the device doesn't have fstab record
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" $mount_point)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|$MOUNT_OPTION)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo "$device $mount_point $device_type defaults,${previous_mount_opts}$MOUNT_OPTION 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif ! grep "$mount_point_match_regexp" /etc/fstab | grep "$MOUNT_OPTION"; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,$MOUNT_OPTION|" /etc/fstab
fi
if mkdir -p "$mount_point"; then
if mountpoint -q "$mount_point"; then
mount -o remount --target "$mount_point"
fi
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure non-root local partitions are mounted with nodev option
mount:
path: '{{ item.mount }}'
src: '{{ item.device }}'
opts: '{{ item.options }},nodev'
state: mounted
fstype: '{{ item.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- item.mount is match('/\w')
- item.options is not search('nodev')
with_items:
- '{{ ansible_facts.mounts }}'
tags:
- 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_nodev_nonroot_local_partitions
- no_reboot_needed
|
Add nosuid Option to /opt
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /opt . The SUID and SGID permissions
should not be required in this directory.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/opt . Rationale:The presence of SUID and SGID executables should be tightly controlled. The
/opt directory contains additional software packages. Users should
not be able to execute SUID or SGID binaries from this directory. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /opt --mountoptions="nosuid"
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="$(printf "[[:space:]]%s[[:space:]]" "/opt")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/opt' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /opt in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /opt)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /opt 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 "nosuid"; 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 "/opt"; then
if mountpoint -q "/opt"; then
mount -o remount --target "/opt"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /opt: Check information associated to mountpoint'
command: findmnt --fstab '/opt'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_opt_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /opt: 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:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_opt_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /opt: If /opt not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /opt
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_opt_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /opt: Make sure nosuid option is part of the to /opt
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:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_opt_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /opt: Ensure /opt is mounted with nosuid option'
mount:
path: /opt
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 ("--fstab"
| length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_opt_nosuid
- no_reboot_needed
|
Add nosuid Option to /srv
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /srv . The SUID and SGID permissions
should not be required in this directory.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/srv . Rationale:The presence of SUID and SGID executables should be tightly controlled. The
/srv directory contains files served by various network services such as FTP. Users should
not be able to execute SUID or SGID binaries from this directory. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /srv --mountoptions="nosuid"
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="$(printf "[[:space:]]%s[[:space:]]" "/srv")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/srv' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /srv in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /srv)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /srv 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 "nosuid"; 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 "/srv"; then
if mountpoint -q "/srv"; then
mount -o remount --target "/srv"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /srv: Check information associated to mountpoint'
command: findmnt --fstab '/srv'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_srv_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /srv: 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:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_srv_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /srv: If /srv not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /srv
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_srv_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /srv: Make sure nosuid option is part of the to /srv
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:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_srv_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /srv: Ensure /srv is mounted with nosuid option'
mount:
path: /srv
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 ("--fstab"
| length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_srv_nosuid
- no_reboot_needed
|
Add noexec Option to /tmp
[ref]ruleThe noexec mount option can be used to prevent binaries
from being executed out of /tmp .
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/tmp . Rationale:Allowing users to execute binaries from world-writable directories
such as /tmp should never be necessary in normal operation and
can expose the system to potential compromise. References:
BP28(R12), 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 Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /tmp --mountoptions="noexec"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/tmp" > /dev/null || findmnt --fstab "/tmp" > /dev/null ); then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/tmp")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /tmp in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /tmp)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /tmp 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 "noexec"; 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 "/tmp"; then
if mountpoint -q "/tmp"; then
mount -o remount --target "/tmp"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add noexec Option to /tmp: Check information associated to mountpoint'
command: findmnt --fstab '/tmp'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
"container"] and "/tmp" in ansible_mounts | map(attribute="mount") | list )
tags:
- 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_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /tmp: 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"]
and "/tmp" in ansible_mounts | map(attribute="mount") | list )
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- 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_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /tmp: If /tmp not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /tmp
- ''
- ''
- defaults
when:
- ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
and "/tmp" in ansible_mounts | map(attribute="mount") | list )
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- 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_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /tmp: Make sure noexec option is part of the to /tmp
options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',noexec''
}) }}'
when:
- ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
and "/tmp" in ansible_mounts | map(attribute="mount") | list )
- mount_info is defined and "noexec" not in mount_info.options
tags:
- 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_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /tmp: Ensure /tmp is mounted with noexec option'
mount:
path: /tmp
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"]
and "/tmp" in ansible_mounts | map(attribute="mount") | list )
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- 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_tmp_noexec
- no_reboot_needed
|
Add nosuid Option to /tmp
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /tmp . 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
/tmp . 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. References:
BP28(R12), 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 Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /tmp --mountoptions="nosuid"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/tmp" > /dev/null || findmnt --fstab "/tmp" > /dev/null ); then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/tmp")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /tmp in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /tmp)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /tmp 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 "nosuid"; 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 "/tmp"; then
if mountpoint -q "/tmp"; then
mount -o remount --target "/tmp"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /tmp: Check information associated to mountpoint'
command: findmnt --fstab '/tmp'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
"container"] and "/tmp" in ansible_mounts | map(attribute="mount") | list )
tags:
- 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_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /tmp: 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"]
and "/tmp" in ansible_mounts | map(attribute="mount") | list )
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- 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_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /tmp: If /tmp not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /tmp
- ''
- ''
- defaults
when:
- ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
and "/tmp" in ansible_mounts | map(attribute="mount") | list )
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- 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_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /tmp: Make sure nosuid option is part of the to /tmp
options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
}) }}'
when:
- ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
and "/tmp" in ansible_mounts | map(attribute="mount") | list )
- mount_info is defined and "nosuid" not in mount_info.options
tags:
- 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_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /tmp: Ensure /tmp is mounted with nosuid option'
mount:
path: /tmp
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"]
and "/tmp" in ansible_mounts | map(attribute="mount") | list )
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- 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_tmp_nosuid
- no_reboot_needed
|
Add noexec Option to /var/log
[ref]ruleThe noexec mount option can be used to prevent binaries
from being executed out of /var/log .
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/var/log . Rationale:Allowing users to execute binaries from directories containing log files
such as /var/log should never be necessary in normal operation and
can expose the system to potential compromise. References:
BP28(R12), CCI-001764, 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 Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/log --mountoptions="noexec"
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="$(printf "[[:space:]]%s[[:space:]]" "/var/log")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/var/log' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /var/log in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /var/log)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /var/log 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 "noexec"; 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 "/var/log"; then
if mountpoint -q "/var/log"; then
mount -o remount --target "/var/log"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add noexec Option to /var/log: Check information associated to mountpoint'
command: findmnt --fstab '/var/log'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- 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_var_log_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/log: 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:
- 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_var_log_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/log: If /var/log not mounted, craft mount_info
manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /var/log
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- 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_var_log_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/log: Make sure noexec option is part of the to
/var/log 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:
- 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_var_log_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/log: Ensure /var/log is mounted with noexec option'
mount:
path: /var/log
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 ("--fstab"
| length == 0)
tags:
- 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_var_log_noexec
- no_reboot_needed
|
Add nosuid Option to /var/log
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /var/log . The SUID and SGID permissions
should not be required in directories containing log files.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/var/log . Rationale:The presence of SUID and SGID executables should be tightly controlled. Users
should not be able to execute SUID or SGID binaries from partitions
designated for log files. References:
BP28(R12), CCI-001764, 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 Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/log --mountoptions="nosuid"
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="$(printf "[[:space:]]%s[[:space:]]" "/var/log")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/var/log' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /var/log in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /var/log)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /var/log 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 "nosuid"; 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 "/var/log"; then
if mountpoint -q "/var/log"; then
mount -o remount --target "/var/log"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /var/log: Check information associated to mountpoint'
command: findmnt --fstab '/var/log'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- 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_var_log_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/log: 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:
- 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_var_log_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/log: If /var/log not mounted, craft mount_info
manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /var/log
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- 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_var_log_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/log: Make sure nosuid option is part of the to
/var/log 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:
- 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_var_log_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/log: Ensure /var/log is mounted with nosuid option'
mount:
path: /var/log
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 ("--fstab"
| length == 0)
tags:
- 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_var_log_nosuid
- no_reboot_needed
|
Add noexec Option to /var
[ref]ruleThe noexec mount option can be used to prevent binaries from being
executed out of /var .
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/var . Rationale:The /var directory contains variable system data such as logs,
mails and caches. No binaries should be executed from this directory. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var --mountoptions="noexec"
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="$(printf "[[:space:]]%s[[:space:]]" "/var")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/var' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /var in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /var)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /var 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 "noexec"; 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 "/var"; then
if mountpoint -q "/var"; then
mount -o remount --target "/var"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add noexec Option to /var: Check information associated to mountpoint'
command: findmnt --fstab '/var'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var: 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:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var: If /var not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /var
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var: Make sure noexec option is part of the to /var
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:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var: Ensure /var is mounted with noexec option'
mount:
path: /var
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 ("--fstab"
| length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_noexec
- no_reboot_needed
|
Add nosuid Option to /var
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /var . The SUID and SGID permissions
should not be required for this directory.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/var . Rationale:The presence of SUID and SGID executables should be tightly controlled. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var --mountoptions="nosuid"
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="$(printf "[[:space:]]%s[[:space:]]" "/var")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/var' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /var in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /var)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /var 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 "nosuid"; 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 "/var"; then
if mountpoint -q "/var"; then
mount -o remount --target "/var"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /var: Check information associated to mountpoint'
command: findmnt --fstab '/var'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- configure_strategy
- high_disruption
- low_complexity
- mount_option_var_nosuid
- no_reboot_needed
- unknown_severity
- name: 'Add nosuid Option to /var: 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:
- configure_strategy
- high_disruption
- low_complexity
- mount_option_var_nosuid
- no_reboot_needed
- unknown_severity
- name: 'Add nosuid Option to /var: If /var not mounted, craft mount_info manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /var
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- mount_option_var_nosuid
- no_reboot_needed
- unknown_severity
- name: 'Add nosuid Option to /var: Make sure nosuid option is part of the to /var
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:
- configure_strategy
- high_disruption
- low_complexity
- mount_option_var_nosuid
- no_reboot_needed
- unknown_severity
- name: 'Add nosuid Option to /var: Ensure /var is mounted with nosuid option'
mount:
path: /var
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 ("--fstab"
| length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- mount_option_var_nosuid
- no_reboot_needed
- unknown_severity
|
Add noexec Option to /var/tmp
[ref]ruleThe noexec mount option can be used to prevent binaries
from being executed out of /var/tmp .
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/var/tmp . Rationale:Allowing users to execute binaries from world-writable directories
such as /var/tmp should never be necessary in normal operation and
can expose the system to potential compromise. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/tmp --mountoptions="noexec"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/var/tmp" > /dev/null || findmnt --fstab "/var/tmp" > /dev/null ); then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/var/tmp")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/var/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /var/tmp in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /var/tmp)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /var/tmp 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 "noexec"; 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 "/var/tmp"; then
if mountpoint -q "/var/tmp"; then
mount -o remount --target "/var/tmp"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add noexec Option to /var/tmp: Check information associated to mountpoint'
command: findmnt --fstab '/var/tmp'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
"container"] and "/var/tmp" in ansible_mounts | map(attribute="mount") | list
)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/tmp: 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"]
and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/tmp: If /var/tmp not mounted, craft mount_info
manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /var/tmp
- ''
- ''
- defaults
when:
- ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/tmp: Make sure noexec option is part of the to
/var/tmp options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',noexec''
}) }}'
when:
- ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
- mount_info is defined and "noexec" not in mount_info.options
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_noexec
- no_reboot_needed
- name: 'Add noexec Option to /var/tmp: Ensure /var/tmp is mounted with noexec option'
mount:
path: /var/tmp
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"]
and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_noexec
- no_reboot_needed
|
Add nosuid Option to /var/tmp
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /var/tmp . 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
/var/tmp . 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. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
part /var/tmp --mountoptions="nosuid"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/var/tmp" > /dev/null || findmnt --fstab "/var/tmp" > /dev/null ); then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/var/tmp")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/var/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /var/tmp in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /var/tmp)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if ! grep "$mount_point_match_regexp" /etc/fstab; 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 " /var/tmp 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 "nosuid"; 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 "/var/tmp"; then
if mountpoint -q "/var/tmp"; then
mount -o remount --target "/var/tmp"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: 'Add nosuid Option to /var/tmp: Check information associated to mountpoint'
command: findmnt --fstab '/var/tmp'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
"container"] and "/var/tmp" in ansible_mounts | map(attribute="mount") | list
)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/tmp: 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"]
and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/tmp: If /var/tmp not mounted, craft mount_info
manually'
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /var/tmp
- ''
- ''
- defaults
when:
- ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/tmp: Make sure nosuid option is part of the to
/var/tmp options'
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
}) }}'
when:
- ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
- mount_info is defined and "nosuid" not in mount_info.options
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_nosuid
- no_reboot_needed
- name: 'Add nosuid Option to /var/tmp: Ensure /var/tmp is mounted with nosuid option'
mount:
path: /var/tmp
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"]
and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_var_tmp_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 14 rules |
Disable Core Dumps
[ref]groupA core dump file is the memory image of an executable
program when it was terminated by the operating system due to
errant behavior. In most cases, only software developers
legitimately need to access these files. The core dump files may
also contain sensitive information, or unnecessarily occupy large
amounts of disk space.
Once a hard limit is set in /etc/security/limits.conf , or
to a file within the /etc/security/limits.d/ directory, a
user cannot increase that limit within his or her own session. If access
to core dumps is required, consider restricting them to only
certain users or groups. See the limits.conf man page for more
information.
The core dumps of setuid programs are further protected. The
sysctl variable fs.suid_dumpable controls whether
the kernel allows core dumps from these programs at all. The default
value of 0 is recommended. |
contains 1 rule |
Disable Core Dumps for SUID programs
[ref]ruleTo set the runtime status of the fs.suid_dumpable kernel parameter, run the following command: $ sudo sysctl -w fs.suid_dumpable=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : fs.suid_dumpable = 0 Rationale:The core dump of a setuid program is more likely to contain
sensitive data, as the program itself runs with greater privileges than the
user who initiated execution of the program. Disabling the ability for any
setuid program to write a core file decreases the risk of unauthorized access
of such data. References:
BP28(R23), 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), 3.3.1.1, 3.3.1.2, 3.3.1.3 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 fs.suid_dumpable from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*fs.suid_dumpable.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "fs.suid_dumpable" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for fs.suid_dumpable
#
/sbin/sysctl -q -n -w fs.suid_dumpable="0"
#
# If fs.suid_dumpable present in /etc/sysctl.conf, change value to "0"
# else, add "fs.suid_dumpable = 0" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^fs.suid_dumpable")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# 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 "^fs.suid_dumpable\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^fs.suid_dumpable\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*fs.suid_dumpable.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- PCI-DSSv4-3.3.1.1
- PCI-DSSv4-3.3.1.2
- PCI-DSSv4-3.3.1.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_suid_dumpable
- name: Comment out any occurrences of fs.suid_dumpable from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*fs.suid_dumpable
replace: '#fs.suid_dumpable'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- PCI-DSSv4-3.3.1.1
- PCI-DSSv4-3.3.1.2
- PCI-DSSv4-3.3.1.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_suid_dumpable
- name: Ensure sysctl fs.suid_dumpable is set to 0
sysctl:
name: fs.suid_dumpable
value: '0'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- PCI-DSSv4-3.3.1.1
- PCI-DSSv4-3.3.1.2
- PCI-DSSv4-3.3.1.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_suid_dumpable
|
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 2 rules |
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=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.kptr_restrict = 2 Rationale:Exposing kernel pointers (through procfs or seq_printf() ) exposes kernel
writeable structures which may contain functions pointers. If a write vulnerability
occurs in the kernel, allowing write access to any of this structure, the kernel can
be compromised. This option disallow any program without the CAP_SYSLOG capability
to get the addresses of kernel pointers by replacing them with 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 /run/sysctl.d/*.conf /usr/local/lib/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
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.kptr_restrict" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
sysctl_kernel_kptr_restrict_value='2'
#
# Set runtime for kernel.kptr_restrict
#
/sbin/sysctl -q -n -w kernel.kptr_restrict="$sysctl_kernel_kptr_restrict_value"
#
# If kernel.kptr_restrict present in /etc/sysctl.conf, change value to appropriate value
# else, add "kernel.kptr_restrict = value" to /etc/sysctl.conf
#
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(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\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.kptr_restrict\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*kernel.kptr_restrict.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- 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 config files
replace:
path: '{{ item.path }}'
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:
- 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 2
tags:
- always
- name: Ensure sysctl kernel.kptr_restrict is set
sysctl:
name: kernel.kptr_restrict
value: '{{ sysctl_kernel_kptr_restrict_value }}'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- 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
|
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. 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), Req-2.2.1, 2.2.3, SRG-OS-000433-GPOS-00193, SRG-OS-000480-GPOS-00227, OL07-00-040201, SV-221846r880630_rule 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 /run/sysctl.d/*.conf /usr/local/lib/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
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.randomize_va_space" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# 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
#
# 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\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.randomize_va_space\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*kernel.randomize_va_space.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040201
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- PCI-DSS-Req-2.2.1
- PCI-DSSv4-2.2.3
- 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 config files
replace:
path: '{{ item.path }}'
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:
- DISA-STIG-OL07-00-040201
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- PCI-DSS-Req-2.2.1
- PCI-DSSv4-2.2.3
- 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'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040201
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- PCI-DSS-Req-2.2.1
- PCI-DSSv4-2.2.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
|
Memory Poisoning
[ref]groupMemory Poisoning consists of writing a special value to uninitialized or freed memory.
Poisoning can be used as a mechanism to prevent leak of information and detection of
corrupted memory. |
contains 2 rules |
Enable page allocator poisoning
[ref]ruleTo enable poisoning of free pages,
add the argument page_poison=1 to the default
GRUB 2 command line for the Linux operating system.
To ensure that page_poison=1 is added as a kernel command line
argument to newly installed kernels, add page_poison=1 to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... page_poison=1 ..."
Run the following command to update command line for already installed kernels:# grubby --update-kernel=ALL --args="page_poison=1" Rationale:Poisoning writes an arbitrary value to freed pages, so any modification or
reference to that page after being freed or before being initialized will be
detected and prevented.
This prevents many types of use-after-free vulnerabilities at little performance cost.
Also prevents leak of data and detection of corrupted memory. Remediation script: (show)
[customizations.kernel]
append = "page_poison=1"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2-common; }; then
# Correct the form of default kernel command line in GRUB
if grep -q '^GRUB_CMDLINE_LINUX=.*page_poison=.*"' '/etc/default/grub' ; then
# modify the GRUB command-line if an page_poison= arg already exists
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)page_poison=[^[:space:]]\+\(.*\"\)/\1page_poison=1\2/" '/etc/default/grub'
else
# no page_poison=arg is present, append it
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)\"/\1 page_poison=1\"/" '/etc/default/grub'
fi
grubby --update-kernel=ALL --args=page_poison=1
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- NIST-800-53-CM-6(a)
- grub2_page_poison_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Check page_poison argument exists
command: grep 'GRUB_CMDLINE_LINUX.*page_poison=' /etc/default/grub
failed_when: false
register: argcheck
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2-common" in ansible_facts.packages'
tags:
- NIST-800-53-CM-6(a)
- grub2_page_poison_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Replace existing page_poison argument
replace:
path: /etc/default/grub
regexp: page_poison=\w+
replace: page_poison=1
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2-common" in ansible_facts.packages'
- argcheck.rc == 0
tags:
- NIST-800-53-CM-6(a)
- grub2_page_poison_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Add page_poison argument
replace:
path: /etc/default/grub
regexp: (GRUB_CMDLINE_LINUX=.*)"
replace: \1 page_poison=1"
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2-common" in ansible_facts.packages'
- argcheck.rc != 0
tags:
- NIST-800-53-CM-6(a)
- grub2_page_poison_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /sbin/grubby --update-kernel=ALL --args="page_poison=1"
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2-common" in ansible_facts.packages'
tags:
- NIST-800-53-CM-6(a)
- grub2_page_poison_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
|
Enable SLUB/SLAB allocator poisoning
[ref]ruleTo enable poisoning of SLUB/SLAB objects,
add the argument slub_debug=FZP to the default
GRUB 2 command line for the Linux operating system.
To ensure that slub_debug=FZP is added as a kernel command line
argument to newly installed kernels, add slub_debug=FZP to the
default Grub2 command line for Linux operating systems. Modify the line within
/etc/default/grub as shown below:
GRUB_CMDLINE_LINUX="... slub_debug=FZP ..."
Run the following command to update command line for already installed kernels:# grubby --update-kernel=ALL --args="slub_debug=FZP" Rationale:Poisoning writes an arbitrary value to freed objects, so any modification or
reference to that object after being freed or before being initialized will be
detected and prevented.
This prevents many types of use-after-free vulnerabilities at little performance cost.
Also prevents leak of data and detection of corrupted memory. Remediation script: (show)
[customizations.kernel]
append = "slub_debug=FZP"
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2-common; }; then
var_slub_debug_options='FZP'
# Correct the form of default kernel command line in GRUB
if grep -q '^GRUB_CMDLINE_LINUX=.*slub_debug=.*"' '/etc/default/grub' ; then
# modify the GRUB command-line if an slub_debug= arg already exists
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)slub_debug=[^[:space:]]\+\(.*\"\)/\1slub_debug=$var_slub_debug_options\2/" '/etc/default/grub'
else
# no slub_debug=arg is present, append it
sed -i "s/\(^GRUB_CMDLINE_LINUX=\".*\)\"/\1 slub_debug=$var_slub_debug_options\"/" '/etc/default/grub'
fi
grubby --update-kernel=ALL --args=slub_debug=$var_slub_debug_options
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- NIST-800-53-CM-6(a)
- grub2_slub_debug_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: XCCDF Value var_slub_debug_options # promote to variable
set_fact:
var_slub_debug_options: !!str FZP
tags:
- always
- name: Check slub_debug argument exists
command: grep 'GRUB_CMDLINE_LINUX.*slub_debug=' /etc/default/grub
failed_when: false
register: argcheck
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2-common" in ansible_facts.packages'
tags:
- NIST-800-53-CM-6(a)
- grub2_slub_debug_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Replace existing slub_debug argument
replace:
path: /etc/default/grub
regexp: slub_debug=\w+
replace: slub_debug={{ var_slub_debug_options }}
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2-common" in ansible_facts.packages'
- argcheck.rc == 0
tags:
- NIST-800-53-CM-6(a)
- grub2_slub_debug_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Add slub_debug argument
replace:
path: /etc/default/grub
regexp: (GRUB_CMDLINE_LINUX=.*)"
replace: \1 slub_debug={{ var_slub_debug_options }}"
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2-common" in ansible_facts.packages'
- argcheck.rc != 0
tags:
- NIST-800-53-CM-6(a)
- grub2_slub_debug_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /sbin/grubby --update-kernel=ALL --args="slub_debug={{ var_slub_debug_options
}}"
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2-common" in ansible_facts.packages'
tags:
- NIST-800-53-CM-6(a)
- grub2_slub_debug_argument
- low_disruption
- medium_complexity
- medium_severity
- reboot_required
- restrict_strategy
|
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. References:
BP28(R23), 3.1.5, CCI-001090, 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, OL07-00-010375, SV-255901r880627_rule 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 /run/sysctl.d/*.conf /usr/local/lib/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
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.dmesg_restrict" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# 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
#
# 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\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.dmesg_restrict\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*kernel.dmesg_restrict.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-010375
- 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 config files
replace:
path: '{{ item.path }}'
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:
- DISA-STIG-OL07-00-010375
- 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'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-010375
- 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
|
Kernel panic on oops
[ref]ruleTo set the runtime status of the kernel.panic_on_oops kernel parameter, run the following command: $ sudo sysctl -w kernel.panic_on_oops=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.panic_on_oops = 1 Warning:
The system may start to panic when it normally wouldn't. A non-catastrophic error that
would have allowed the system to continue operating will now result in a panic. Rationale:An attacker trying to exploit the kernel may trigger kernel OOPSes,
panicking the system will impede them from continuing. 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.panic_on_oops from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*kernel.panic_on_oops.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.panic_on_oops" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for kernel.panic_on_oops
#
/sbin/sysctl -q -n -w kernel.panic_on_oops="1"
#
# If kernel.panic_on_oops present in /etc/sysctl.conf, change value to "1"
# else, add "kernel.panic_on_oops = 1" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.panic_on_oops")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$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.panic_on_oops\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.panic_on_oops\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*kernel.panic_on_oops.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_panic_on_oops
- name: Comment out any occurrences of kernel.panic_on_oops from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*kernel.panic_on_oops
replace: '#kernel.panic_on_oops'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_panic_on_oops
- name: Ensure sysctl kernel.panic_on_oops is set to 1
sysctl:
name: kernel.panic_on_oops
value: '1'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_panic_on_oops
|
Limit CPU consumption of the Perf system
[ref]ruleTo set the runtime status of the kernel.perf_cpu_time_max_percent kernel parameter, run the following command: $ sudo sysctl -w kernel.perf_cpu_time_max_percent=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.perf_cpu_time_max_percent = 1 Rationale:The kernel.perf_cpu_time_max_percent configures a treshold of
maximum percentile of CPU that can be used by Perf system. Restricting usage
of Perf system decreases risk of potential availability problems. 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.perf_cpu_time_max_percent from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*kernel.perf_cpu_time_max_percent.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.perf_cpu_time_max_percent" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for kernel.perf_cpu_time_max_percent
#
/sbin/sysctl -q -n -w kernel.perf_cpu_time_max_percent="1"
#
# If kernel.perf_cpu_time_max_percent present in /etc/sysctl.conf, change value to "1"
# else, add "kernel.perf_cpu_time_max_percent = 1" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.perf_cpu_time_max_percent")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$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.perf_cpu_time_max_percent\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.perf_cpu_time_max_percent\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*kernel.perf_cpu_time_max_percent.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_perf_cpu_time_max_percent
- name: Comment out any occurrences of kernel.perf_cpu_time_max_percent from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*kernel.perf_cpu_time_max_percent
replace: '#kernel.perf_cpu_time_max_percent'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_perf_cpu_time_max_percent
- name: Ensure sysctl kernel.perf_cpu_time_max_percent is set to 1
sysctl:
name: kernel.perf_cpu_time_max_percent
value: '1'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_perf_cpu_time_max_percent
|
Limit sampling frequency of the Perf system
[ref]ruleTo set the runtime status of the kernel.perf_event_max_sample_rate kernel parameter, run the following command: $ sudo sysctl -w kernel.perf_event_max_sample_rate=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.perf_event_max_sample_rate = 1 Rationale:The kernel.perf_event_max_sample_rate parameter configures maximum
frequency of collecting of samples for the Perf system. It is expressed in
samples per second. Restricting usage of Perf system decreases risk
of potential availability problems. 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.perf_event_max_sample_rate from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*kernel.perf_event_max_sample_rate.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.perf_event_max_sample_rate" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for kernel.perf_event_max_sample_rate
#
/sbin/sysctl -q -n -w kernel.perf_event_max_sample_rate="1"
#
# If kernel.perf_event_max_sample_rate present in /etc/sysctl.conf, change value to "1"
# else, add "kernel.perf_event_max_sample_rate = 1" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.perf_event_max_sample_rate")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$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.perf_event_max_sample_rate\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.perf_event_max_sample_rate\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*kernel.perf_event_max_sample_rate.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_perf_event_max_sample_rate
- name: Comment out any occurrences of kernel.perf_event_max_sample_rate from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*kernel.perf_event_max_sample_rate
replace: '#kernel.perf_event_max_sample_rate'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_perf_event_max_sample_rate
- name: Ensure sysctl kernel.perf_event_max_sample_rate is set to 1
sysctl:
name: kernel.perf_event_max_sample_rate
value: '1'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_perf_event_max_sample_rate
|
Disallow kernel profiling by unprivileged users
[ref]ruleTo set the runtime status of the kernel.perf_event_paranoid kernel parameter, run the following command: $ sudo sysctl -w kernel.perf_event_paranoid=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.perf_event_paranoid = 2 Rationale:Kernel profiling can reveal sensitive information about kernel behaviour. 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.perf_event_paranoid from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*kernel.perf_event_paranoid.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.perf_event_paranoid" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for kernel.perf_event_paranoid
#
/sbin/sysctl -q -n -w kernel.perf_event_paranoid="2"
#
# If kernel.perf_event_paranoid present in /etc/sysctl.conf, change value to "2"
# else, add "kernel.perf_event_paranoid = 2" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.perf_event_paranoid")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$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.perf_event_paranoid\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.perf_event_paranoid\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*kernel.perf_event_paranoid.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-AC-6
- disable_strategy
- low_complexity
- low_severity
- medium_disruption
- reboot_required
- sysctl_kernel_perf_event_paranoid
- name: Comment out any occurrences of kernel.perf_event_paranoid from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*kernel.perf_event_paranoid
replace: '#kernel.perf_event_paranoid'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-AC-6
- disable_strategy
- low_complexity
- low_severity
- medium_disruption
- reboot_required
- sysctl_kernel_perf_event_paranoid
- name: Ensure sysctl kernel.perf_event_paranoid is set to 2
sysctl:
name: kernel.perf_event_paranoid
value: '2'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-AC-6
- disable_strategy
- low_complexity
- low_severity
- medium_disruption
- reboot_required
- sysctl_kernel_perf_event_paranoid
|
Configure maximum number of process identifiers
[ref]ruleTo set the runtime status of the kernel.pid_max kernel parameter, run the following command: $ sudo sysctl -w kernel.pid_max=65536
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.pid_max = 65536 Rationale:The kernel.pid_max parameter configures upper limit on process
identifiers (PID). If this number is not high enough, it might happen that
forking of new processes is not possible, because all available PIDs are
exhausted. Increasing this number enhances availability. 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.pid_max from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*kernel.pid_max.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.pid_max" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for kernel.pid_max
#
/sbin/sysctl -q -n -w kernel.pid_max="65536"
#
# If kernel.pid_max present in /etc/sysctl.conf, change value to "65536"
# else, add "kernel.pid_max = 65536" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.pid_max")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "65536"
# 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.pid_max\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.pid_max\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*kernel.pid_max.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_pid_max
- name: Comment out any occurrences of kernel.pid_max from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*kernel.pid_max
replace: '#kernel.pid_max'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_pid_max
- name: Ensure sysctl kernel.pid_max is set to 65536
sysctl:
name: kernel.pid_max
value: '65536'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_pid_max
|
Disallow magic SysRq key
[ref]ruleTo set the runtime status of the kernel.sysrq kernel parameter, run the following command: $ sudo sysctl -w kernel.sysrq=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.sysrq = 0 Rationale:The Magic SysRq key allows sending certain commands directly to the running
kernel. It can dump various system and process information, potentially
revealing sensitive information. It can also reboot or shutdown the machine,
disturbing its availability. 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.sysrq from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*kernel.sysrq.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.sysrq" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for kernel.sysrq
#
/sbin/sysctl -q -n -w kernel.sysrq="0"
#
# If kernel.sysrq present in /etc/sysctl.conf, change value to "0"
# else, add "kernel.sysrq = 0" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.sysrq")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# 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.sysrq\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.sysrq\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*kernel.sysrq.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_sysrq
- name: Comment out any occurrences of kernel.sysrq from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*kernel.sysrq
replace: '#kernel.sysrq'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_sysrq
- name: Ensure sysctl kernel.sysrq is set to 0
sysctl:
name: kernel.sysrq
value: '0'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_sysrq
|
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 /run/sysctl.d/*.conf /usr/local/lib/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
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.yama.ptrace_scope" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# 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
#
# 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\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.yama.ptrace_scope\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*kernel.yama.ptrace_scope.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- 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 config files
replace:
path: '{{ item.path }}'
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:
- 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'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-SC-7(10)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_yama_ptrace_scope
|
Prevent applications from mapping low portion of virtual memory
[ref]ruleTo set the runtime status of the vm.mmap_min_addr kernel parameter, run the following command: $ sudo sysctl -w vm.mmap_min_addr=65536
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : vm.mmap_min_addr = 65536 Rationale:The vm.mmap_min_addr parameter specifies the minimum virtual
address that a process is allowed to mmap. Allowing a process to mmap low
portion of virtual memory can have security implications such as such as
heightened risk of kernel null pointer dereference defects. 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 vm.mmap_min_addr from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*vm.mmap_min_addr.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "vm.mmap_min_addr" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE="/etc/sysctl.conf"
#
# Set runtime for vm.mmap_min_addr
#
/sbin/sysctl -q -n -w vm.mmap_min_addr="65536"
#
# If vm.mmap_min_addr present in /etc/sysctl.conf, change value to "65536"
# else, add "vm.mmap_min_addr = 65536" to /etc/sysctl.conf
#
# 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=$(sed 's/[\^=\$,;+]*//g' <<< "^vm.mmap_min_addr")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "65536"
# 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 "^vm.mmap_min_addr\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^vm.mmap_min_addr\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
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/
- /run/sysctl.d/
- /usr/local/lib/sysctl.d/
contains: ^[\s]*vm.mmap_min_addr.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_vm_mmap_min_addr
- name: Comment out any occurrences of vm.mmap_min_addr from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*vm.mmap_min_addr
replace: '#vm.mmap_min_addr'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_vm_mmap_min_addr
- name: Ensure sysctl vm.mmap_min_addr is set to 65536
sysctl:
name: vm.mmap_min_addr
value: '65536'
sysctl_file: /etc/sysctl.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_vm_mmap_min_addr
|
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 Oracle Linux 7, 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 Oracle Linux 7 system, unless that
system has unusual requirements which make a stronger policy
appropriate.
For more information on SELinux, see https://docs.oracle.com/en/operating-systems/oracle-linux/selinux/. |
contains 2 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 |
Configure the polyinstantiation_enabled SELinux Boolean
[ref]ruleBy default, the SELinux boolean polyinstantiation_enabled is disabled.
This setting should be configured to true.
To set the polyinstantiation_enabled SELinux boolean, run the following command:
$ sudo setsebool -P polyinstantiation_enabled true Rationale:Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if ! ( [ "${container:-}" == "bwrap-osbuild" ] ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_polyinstantiation_enabled='true'
setsebool -P polyinstantiation_enabled $var_polyinstantiation_enabled
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: XCCDF Value var_polyinstantiation_enabled # promote to variable
set_fact:
var_polyinstantiation_enabled: !!str true
tags:
- always
- name: Ensure libsemanage-python installed
package:
name: libsemanage-python
state: present
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( lookup("env", "container") == "bwrap-osbuild" )
tags:
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- sebool_polyinstantiation_enabled
- name: Set SELinux boolean polyinstantiation_enabled accordingly
seboolean:
name: polyinstantiation_enabled
state: '{{ var_polyinstantiation_enabled }}'
persistent: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( lookup("env", "container") == "bwrap-osbuild" )
tags:
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- sebool_polyinstantiation_enabled
|
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. 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-001084, 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-000134-GPOS-00068, OL07-00-020210, SV-221716r853675_rule 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 |
---|
Reboot: | false |
---|
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:
- DISA-STIG-OL07-00-020210
- 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)
- high_severity
- low_complexity
- low_disruption
- 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 Oracle Linux 7 installs on a system and disable software which is not needed. It
then enumerates the software packages installed on a default Oracle Linux 7 system and provides guidance about which
ones can be safely disabled.
Oracle Linux 7 provides a convenient minimal install option that essentially installs the bare necessities for a functional
system. When building Oracle Linux 7 systems, it is highly recommended to select the minimal packages and then build up
the system from there. |
contains 19 rules |
The Dynamic Host Configuration Protocol (DHCP) allows
systems to request and obtain an IP address and other configuration
parameters from a server.
This guide recommends configuring networking on clients by manually editing
the appropriate files under /etc/sysconfig . Use of DHCP can make client
systems vulnerable to compromise by rogue DHCP servers, and should be avoided
unless necessary. If using DHCP is necessary, however, there are best practices
that should be followed to minimize security risk. |
contains 1 rule |
Disable DHCP Server
[ref]groupThe DHCP server dhcpd is not installed or activated by
default. If the software was installed and activated, but the
system does not need to act as a DHCP server, it should be disabled
and removed. |
contains 1 rule |
Uninstall DHCP Server Package
[ref]ruleIf the system does not need to act as a DHCP server,
the dhcp package can be uninstalled.
The dhcp package can be removed with the following command:
$ sudo yum erase dhcp Rationale:Removing the DHCP server ensures that it cannot be easily or
accidentally reactivated and disrupt network operation. References:
BP28(R1), 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, 2.2.4 Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=dhcp
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_dhcp
class remove_dhcp {
package { 'dhcp':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove dhcp
# from the system, and may remove any packages
# that depend on dhcp. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "dhcp" ; then
yum remove -y "dhcp"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure dhcp is removed
package:
name: dhcp
state: absent
tags:
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_dhcp_removed
|
Mail Server Software
[ref]groupMail servers are used to send and receive email over the network.
Mail is a very common service, and Mail Transfer Agents (MTAs) are obvious
targets of network attack.
Ensure that systems are not running MTAs unnecessarily,
and configure needed MTAs as defensively as possible.
Very few systems at any site should be configured to directly receive email over the
network. Users should instead use mail client programs to retrieve email
from a central server that supports protocols such as IMAP or POP3.
However, it is normal for most systems to be independently capable of sending email,
for instance so that cron jobs can report output to an administrator.
Most MTAs, including Postfix, support a submission-only mode in which mail can be sent from
the local system to a central site MTA (or directly delivered to a local account),
but the system still cannot receive mail directly over a network.
The alternatives program in Oracle Linux 7 permits selection of other mail server software
(such as Sendmail), but Postfix is the default and is preferred.
Postfix was coded with security in mind and can also be more effectively contained by
SELinux as its modular design has resulted in separate processes performing specific actions.
More information is available on its website,
http://www.postfix.org. |
contains 3 rules |
Configure SMTP For Mail Clients
[ref]groupThis section discusses settings for Postfix in a submission-only
e-mail configuration. |
contains 2 rules |
Configure System to Forward All Mail For The Root Account
[ref]ruleMake sure that mails delivered to root user are forwarded to a monitored
email address. Make sure that the address
system.administrator@mail.mil is a valid email address
reachable from the system in question. Use the following command to
configure the alias:
$ sudo echo "root: system.administrator@mail.mil" >> /etc/aliases
$ sudo newaliases Rationale:A number of system services utilize email messages sent to the root user to
notify system administrators of active or impending issues. These messages must
be forwarded to at least one monitored email address. |
Disable Postfix Network Listening
[ref]ruleEdit the file /etc/postfix/main.cf to ensure that only the following
inet_interfaces line appears:
inet_interfaces = loopback-only Rationale:This ensures postfix accepts mail messages
(such as cron job reports) from the local system only,
and not from the network, which protects it from network attack. References:
BP28(R48), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000382, 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, 2.2.4 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q postfix; }; then
var_postfix_inet_interfaces='loopback-only'
if [ -e "/etc/postfix/main.cf" ] ; then
LC_ALL=C sed -i "/^\s*inet_interfaces\s\+=\s\+/Id" "/etc/postfix/main.cf"
else
touch "/etc/postfix/main.cf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/postfix/main.cf"
cp "/etc/postfix/main.cf" "/etc/postfix/main.cf.bak"
# Insert at the end of the file
printf '%s\n' "inet_interfaces=$var_postfix_inet_interfaces" >> "/etc/postfix/main.cf"
# Clean up after ourselves.
rm "/etc/postfix/main.cf.bak"
systemctl restart postfix
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_postfix_inet_interfaces # promote to variable
set_fact:
var_postfix_inet_interfaces: !!str loopback-only
tags:
- always
- name: Gather list of packages
package_facts:
manager: auto
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ''
tags:
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.4
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- postfix_network_listening_disabled
- restrict_strategy
- name: Make changes to Postfix configuration file
lineinfile:
path: /etc/postfix/main.cf
create: false
regexp: ^inet_interfaces\s*=\s.*
line: inet_interfaces = {{ var_postfix_inet_interfaces }}
state: present
insertafter: ^inet_interfaces\s*=\s.*
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"postfix" in ansible_facts.packages'
- '"postfix" in ansible_facts.packages'
tags:
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.4
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- postfix_network_listening_disabled
- restrict_strategy
|
Uninstall Sendmail Package
[ref]ruleSendmail is not the default mail transfer agent and is
not installed by default.
The sendmail package can be removed with the following command:
$ sudo yum erase sendmail Rationale:The sendmail software was not developed with security in mind and
its design prevents it from being effectively contained by SELinux. Postfix
should be used instead. References:
BP28(R1), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000381, 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, SRG-OS-000480-GPOS-00227, SRG-OS-000095-GPOS-00049 Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=sendmail
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_sendmail
class remove_sendmail {
package { 'sendmail':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# CAUTION: This remediation script will remove sendmail
# from the system, and may remove any packages
# that depend on sendmail. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "sendmail" ; then
yum remove -y "sendmail"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure sendmail is removed
package:
name: sendmail
state: absent
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- 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
- package_sendmail_removed
|
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 Oracle Linux 7
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 11 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 Oracle Linux 7. |
contains 1 rule |
Uninstall xinetd Package
[ref]ruleThe xinetd package can be removed with the following command:
$ sudo yum erase xinetd Rationale:Removing the xinetd package decreases the risk of the
xinetd service's accidental (or intentional) activation. 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, 2.2.4 Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=xinetd
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_xinetd
class remove_xinetd {
package { 'xinetd':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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
yum remove -y "xinetd"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure xinetd is removed
package:
name: xinetd
state: absent
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_xinetd_removed
|
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 2 rules |
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 Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=ypbind
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_ypbind
class remove_ypbind {
package { 'ypbind':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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
yum remove -y "ypbind"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure ypbind is removed
package:
name: ypbind
state: absent
tags:
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- package_ypbind_removed
- unknown_severity
|
Uninstall ypserv Package
[ref]ruleThe ypserv package can be removed with the following command:
$ sudo yum erase ypserv Rationale:The NIS service provides an unencrypted authentication service which does
not provide for the confidentiality and integrity of user passwords or the
remote session.
Removing the ypserv package decreases the risk of the accidental
(or intentional) activation of NIS or NIS+ services. 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, Req-2.2.2, 2.2.4, SRG-OS-000095-GPOS-00049, OL07-00-020010, SV-221705r603260_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=ypserv
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_ypserv
class remove_ypserv {
package { 'ypserv':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove ypserv
# from the system, and may remove any packages
# that depend on ypserv. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "ypserv" ; then
yum remove -y "ypserv"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure ypserv is removed
package:
name: ypserv
state: absent
tags:
- DISA-STIG-OL07-00-020010
- 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)
- PCI-DSS-Req-2.2.2
- PCI-DSSv4-2.2.4
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_ypserv_removed
|
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 yum 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. 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, OL07-00-020000, SV-221704r603260_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=rsh-server
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_rsh-server
class remove_rsh-server {
package { 'rsh-server':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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
yum remove -y "rsh-server"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure rsh-server is removed
package:
name: rsh-server
state: absent
tags:
- DISA-STIG-OL07-00-020000
- 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
|
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 . 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, 2.2.4 Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=rsh
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_rsh
class remove_rsh {
package { 'rsh':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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
yum remove -y "rsh"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure rsh is removed
package:
name: rsh
state: absent
tags:
- NIST-800-171-3.1.13
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- package_rsh_removed
- unknown_severity
|
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 yum 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 Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=talk-server
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_talk-server
class remove_talk-server {
package { 'talk-server':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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
yum remove -y "talk-server"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure talk-server is removed
package:
name: talk-server
state: absent
tags:
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_talk-server_removed
|
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 yum 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 Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=talk
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_talk
class remove_talk {
package { 'talk':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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
yum remove -y "talk"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure talk is removed
package:
name: talk
state: absent
tags:
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_talk_removed
|
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 2 rules |
Uninstall telnet-server Package
[ref]ruleThe telnet-server package can be removed with the following command:
$ sudo yum 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. 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, Req-2.2.2, 2.2.4, SRG-OS-000095-GPOS-00049, OL07-00-021710, SV-221763r603260_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=telnet-server
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_telnet-server
class remove_telnet-server {
package { 'telnet-server':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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
yum remove -y "telnet-server"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure telnet-server is removed
package:
name: telnet-server
state: absent
tags:
- DISA-STIG-OL07-00-021710
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-2.2.2
- PCI-DSSv4-2.2.4
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_telnet-server_removed
|
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 Oracle Linux 7. 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, 2.2.4 Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=telnet
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_telnet
class remove_telnet {
package { 'telnet':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
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
yum remove -y "telnet"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure telnet is removed
package:
name: telnet
state: absent
tags:
- NIST-800-171-3.1.13
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_telnet_removed
|
TFTP Server
[ref]groupTFTP is a lightweight version of the FTP protocol which has
traditionally been used to configure networking equipment. However,
TFTP provides little security, and modern versions of networking
operating systems frequently support configuration via SSH or other
more secure protocols. A TFTP server should be run only if no more
secure method of supporting existing equipment can be
found. |
contains 2 rules |
Uninstall tftp-server Package
[ref]ruleThe tftp-server package can be removed with the following command: $ sudo yum erase tftp-server Rationale:Removing the tftp-server package decreases the risk of the accidental
(or intentional) activation of tftp services.
If TFTP is required for operational support (such as transmission of router
configurations), its use must be documented with the Information Systems
Securty Manager (ISSM), restricted to only authorized personnel, and have
access control rules established. 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-000318, CCI-000366, CCI-000368, CCI-001812, CCI-001813, CCI-001814, 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-000480-GPOS-00227, OL07-00-040700, SV-221885r603260_rule Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=tftp-server
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_tftp-server
class remove_tftp-server {
package { 'tftp-server':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove tftp-server
# from the system, and may remove any packages
# that depend on tftp-server. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "tftp-server" ; then
yum remove -y "tftp-server"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure tftp-server is removed
package:
name: tftp-server
state: absent
tags:
- DISA-STIG-OL07-00-040700
- 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_tftp-server_removed
|
Remove tftp Daemon
[ref]ruleTrivial File Transfer Protocol (TFTP) is a simple file transfer protocol,
typically used to automatically transfer configuration or boot files between systems.
TFTP does not support authentication and can be easily hacked. The package
tftp is a client program that allows for connections to a tftp server. Rationale:It is recommended that TFTP be removed, unless there is a specific need
for TFTP (such as a boot server). In that case, use extreme caution when configuring
the services. Remediation Anaconda snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
package --remove=tftp
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_tftp
class remove_tftp {
package { 'tftp':
ensure => 'purged',
}
}
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove tftp
# from the system, and may remove any packages
# that depend on tftp. Execute this
# remediation AFTER testing on a non-production
# system!
if rpm -q --quiet "tftp" ; then
yum remove -y "tftp"
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure tftp is removed
package:
name: tftp
state: absent
tags:
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_tftp_removed
|
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 4 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 3 rules |
Set SSH Client Alive Count Max
[ref]ruleThe SSH server sends at most ClientAliveCountMax messages
during a SSH session and waits for a response from the SSH client.
The option ClientAliveInterval configures timeout after
each ClientAliveCountMax message. If the SSH server does not
receive a response from the client, then the connection is considered unresponsive
and terminated.
For SSH earlier than v8.2, a ClientAliveCountMax value of 0
causes a timeout precisely when the ClientAliveInterval is set.
Starting with v8.2, a value of 0 disables the timeout functionality
completely. If the option is set to a number greater than 0 , then
the session will be disconnected after
ClientAliveInterval * ClientAliveCountMax seconds without receiving
a keep alive message. Rationale:This ensures a user login will be terminated as soon as the ClientAliveInterval
is reached. References:
BP28(R29), 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 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, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, 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, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, 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 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, 8.2.8, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_sshd_set_keepalive='0'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*ClientAliveCountMax\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' "ClientAliveCountMax $var_sshd_set_keepalive" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "ClientAliveCountMax $var_sshd_set_keepalive" >> "/etc/ssh/sshd_config"
tail -n "+$(( 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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sshd_set_keepalive # promote to variable
set_fact:
var_sshd_set_keepalive: !!str 0
tags:
- always
- name: Set SSH Client Alive Count Max
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*ClientAliveCountMax\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*ClientAliveCountMax\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*ClientAliveCountMax\s+
line: ClientAliveCountMax {{ var_sshd_set_keepalive }}
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CJIS-5.5.6
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_keepalive
|
Set SSH Client Alive Interval
[ref]ruleSSH allows administrators to set a network responsiveness timeout interval.
After this interval has passed, the unresponsive client will be automatically logged out.
To set this timeout interval, edit the following line in /etc/ssh/sshd_config as
follows:
ClientAliveInterval 600
The timeout interval is given in seconds. For example, have a timeout
of 10 minutes, set interval to 600.
If a shorter timeout has already been set for the login shell, that value will
preempt any SSH setting made in /etc/ssh/sshd_config . Keep in mind that
some processes may stop SSH from correctly detecting that the user is idle.Warning:
SSH disconnecting unresponsive clients will not have desired effect without also
configuring ClientAliveCountMax in the SSH service configuration. Warning:
Following conditions may prevent the SSH session to time out:
- Remote processes on the remote machine generates output. As the output has to be transferred over the network to the client, the timeout is reset every time such transfer happens.
- Any
scp or sftp activity by the same user to the host resets the timeout.
Rationale:Terminating an idle ssh session within a short time period reduces the window of
opportunity for unauthorized personnel to take control of a management session
enabled on the console or console port that has been let unattended. References:
BP28(R29), 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 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, 4.3.4.3.3, 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, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, 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 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CM-6(a), AC-17(a), AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, 8.2.8, SRG-OS-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SRG-OS-000395-GPOS-00175, OL07-00-040320, SV-221849r853721_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sshd_idle_timeout_value='600'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*ClientAliveInterval\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' "ClientAliveInterval $sshd_idle_timeout_value" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "ClientAliveInterval $sshd_idle_timeout_value" >> "/etc/ssh/sshd_config"
tail -n "+$(( 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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value sshd_idle_timeout_value # promote to variable
set_fact:
sshd_idle_timeout_value: !!str 600
tags:
- always
- name: Set SSH Client Alive Interval
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*ClientAliveInterval\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*ClientAliveInterval\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*ClientAliveInterval\s+
line: ClientAliveInterval {{ sshd_idle_timeout_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:
- CJIS-5.5.6
- DISA-STIG-OL07-00-040320
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_idle_timeout
|
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 :
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. 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, FAU_GEN.1, Req-2.2.4, 2.2.6, SRG-OS-000109-GPOS-00056, SRG-OS-000480-GPOS-00227, OL07-00-040370, SV-221854r603260_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PermitRootLogin\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 "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PermitRootLogin no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "PermitRootLogin no" >> "/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 |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable SSH Root Login
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitRootLogin\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*PermitRootLogin\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*PermitRootLogin\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:
- CJIS-5.5.6
- DISA-STIG-OL07-00-040370
- 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)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_root_login
|
Verify Permissions on SSH Server Private *_key Key Files
[ref]ruleSSH server private keys - files that match the /etc/ssh/*_key glob, have to have restricted permissions.
If those files are owned by the root user and the root group, they have to have the 0600 permission or stricter.
If they are owned by the root user, but by a dedicated group ssh_keys , they can have the 0640 permission or stricter. Rationale:If an unauthorized user obtains the private SSH host key file, the host could be
impersonated. 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, Req-2.2.4, 2.2.6, SRG-OS-000480-GPOS-00227, OL07-00-040420, SV-221859r880579_rule 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'
}
}
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
for keyfile in /etc/ssh/*_key; do
test -f "$keyfile" || continue
if test root:root = "$(stat -c "%U:%G" "$keyfile")"; then
chmod u-xs,g-xwrs,o-xwrt "$keyfile"
elif test root:ssh_keys = "$(stat -c "%U:%G" "$keyfile")"; then
chmod u-xs,g-xws,o-xwrt "$keyfile"
else
echo "Key-like file '$keyfile' is owned by an unexpected user:group combination"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find root:root-owned keys
ansible.builtin.command: find -H /etc/ssh/ -maxdepth 1 -user root -regex ".*_key$"
-type f -group root -perm /u+xs,g+xwrs,o+xwrt
register: root_owned_keys
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040420
- 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)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_sshd_private_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for root:root-owned keys
ansible.builtin.file:
path: '{{ item }}'
mode: u-xs,g-xwrs,o-xwrt
state: file
with_items:
- '{{ root_owned_keys.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040420
- 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)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_sshd_private_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Find root:ssh_keys-owned keys
ansible.builtin.command: find -H /etc/ssh/ -maxdepth 1 -user root -regex ".*_key$"
-type f -group ssh_keys -perm /u+xs,g+xws,o+xwrt
register: dedicated_group_owned_keys
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040420
- 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)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_sshd_private_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for root:ssh_keys-owned keys
ansible.builtin.file:
path: '{{ item }}'
mode: u-xs,g-xws,o-xwrt
state: file
with_items:
- '{{ dedicated_group_owned_keys.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- DISA-STIG-OL07-00-040420
- 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)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_sshd_private_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
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