| CCE ID |
Rule Title |
Description |
|
Install AIDE |
The aide package can be installed with the following command:
$ sudo dnf install aide
|
|
Build and Test AIDE Database |
Run 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. |
|
Configure AIDE to Verify the Audit Tools |
The operating system file integrity tool must be configured to protect the integrity of the audit tools. |
|
Configure Periodic Execution of AIDE |
At a minimum, AIDE should be configured to run a weekly scan.
To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab:
05 4 * * * root /usr/sbin/aide --check
To implement a weekly execution of AIDE at 4:05am using cron, add the following line to /etc/crontab:
05 4 * * 0 root /usr/sbin/aide --check
AIDE can be executed periodically through other means; this is merely one example.
The usage of cron's special time codes, such as @daily and
@weekly is acceptable. |
|
Configure System Cryptography Policy |
To configure the system cryptography policy to use ciphers only from the $ sudo update-crypto-policies --set
The rule checks if settings for selected crypto policy are configured as expected. Configuration files in the /etc/crypto-policies/back-ends are either symlinks to correct files provided by Crypto-policies package or they are regular files in case crypto policy customizations are applied.
Crypto policies may be customized by crypto policy modules, in which case it is delimited from the base policy using a colon. |
|
Configure SSH to use System Crypto Policy |
Crypto Policies provide a centralized control over crypto algorithms usage of many packages.
SSH is supported by crypto policy, but the SSH configuration may be
set up to ignore it.
To check that Crypto Policies settings are configured correctly, ensure that
the CRYPTO_POLICY variable is either commented or not set at all
in the /etc/sysconfig/sshd. |
|
Ensure /dev/shm is configured |
The /dev/shm is a traditional shared memory concept.
One program will create a memory portion, which other processes
(if permitted) can access. If /dev/shm is not configured,
tmpfs will be mounted to /dev/shm by systemd. |
|
Ensure /home Located On Separate Partition |
If 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. |
|
Ensure /tmp Located On Separate Partition |
The /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. |
|
Ensure /var Located On Separate Partition |
The /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. |
|
Ensure /var/log Located On Separate Partition |
System 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. |
|
Ensure /var/log/audit Located On Separate Partition |
Audit logs are stored in the /var/log/audit directory.
Ensure that /var/log/audit has its own partition or logical
volume at installation time, or migrate it using LVM.
Make absolutely certain that it is large enough to store all
audit logs that will be created by the auditing daemon. |
|
Ensure /var/tmp Located On Separate Partition |
The /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. |
|
Install sudo Package |
The sudo package can be installed with the following command:
$ sudo dnf install sudo
|
|
Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo use_pty |
The 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/. |
|
Ensure Sudo Logfile Exists - sudo logfile |
A custom log sudo file can be configured with the 'logfile' tag. This rule configures
a sudo custom logfile at the default location suggested by CIS, which uses
/var/log/sudo.log. |
|
Require Re-Authentication When Using the sudo Command |
The sudo timestamp_timeout tag sets the amount of time sudo password prompt waits.
The default timestamp_timeout value is 5 minutes.
The timestamp_timeout should be configured by making sure that the
timestamp_timeout tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/.
If the value is set to an integer less than 0, the user's time stamp will not expire
and the user will not have to re-authenticate for privileged actions until the user's session is terminated. |
|
Ensure gpgcheck Enabled In Main dnf Configuration |
The gpgcheck option controls whether
RPM packages' signatures are always checked prior to installation.
To configure dnf to check package signatures before installing
them, ensure the following line appears in /etc/dnf/dnf.conf in
the [main] section:
gpgcheck=1
|
|
Modify the System Login Banner |
To configure the system login banner edit /etc/issue. Replace the
default text with a message compliant with the local site policy or a legal
disclaimer.
The DoD required text is either:
You are accessing a U.S. Government (USG) Information System (IS) that
is provided for USG-authorized use only. By using this IS (which includes
any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS
for purposes including, but not limited to, penetration testing, COMSEC
monitoring, network operations and defense, personnel misconduct (PM), law
enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private,
are subject to routine monitoring, interception, and search, and may be
disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access
controls) to protect USG interests -- not for your personal benefit or
privacy.
-Notwithstanding the above, using this IS does not constitute consent
to PM, LE or CI investigative searching or monitoring of the content of
privileged communications, or work product, related to personal
representation or services by attorneys, psychotherapists, or clergy, and
their assistants. Such communications and work product are private and
confidential. See User Agreement for details.
OR:
I've read & consent to terms in IS user agreem't.
|
|
Modify the System Login Banner for Remote Connections |
To configure the system login banner edit /etc/issue.net. Replace the
default text with a message compliant with the local site policy or a legal
disclaimer.
The DoD required text is either:
You are accessing a U.S. Government (USG) Information System (IS) that
is provided for USG-authorized use only. By using this IS (which includes
any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS
for purposes including, but not limited to, penetration testing, COMSEC
monitoring, network operations and defense, personnel misconduct (PM), law
enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private,
are subject to routine monitoring, interception, and search, and may be
disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access
controls) to protect USG interests -- not for your personal benefit or
privacy.
-Notwithstanding the above, using this IS does not constitute consent
to PM, LE or CI investigative searching or monitoring of the content of
privileged communications, or work product, related to personal
representation or services by attorneys, psychotherapists, or clergy, and
their assistants. Such communications and work product are private and
confidential. See User Agreement for details.
OR:
I've read & consent to terms in IS user agreem't.
|
|
Modify the System Message of the Day Banner |
To configure the system message banner edit /etc/motd. Replace the
default text with a message compliant with the local site policy or a legal
disclaimer.
The DoD required text is either:
You are accessing a U.S. Government (USG) Information System (IS) that
is provided for USG-authorized use only. By using this IS (which includes
any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS
for purposes including, but not limited to, penetration testing, COMSEC
monitoring, network operations and defense, personnel misconduct (PM), law
enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private,
are subject to routine monitoring, interception, and search, and may be
disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access
controls) to protect USG interests -- not for your personal benefit or
privacy.
-Notwithstanding the above, using this IS does not constitute consent
to PM, LE or CI investigative searching or monitoring of the content of
privileged communications, or work product, related to personal
representation or services by attorneys, psychotherapists, or clergy, and
their assistants. Such communications and work product are private and
confidential. See User Agreement for details.
OR:
I've read & consent to terms in IS user agreem't.
|
|
Verify Group Ownership of System Login Banner |
To properly set the group owner of /etc/issue, run the command:
$ sudo chgrp root /etc/issue
|
|
Verify Group Ownership of System Login Banner for Remote Connections |
To properly set the group owner of /etc/issue.net, run the command:
$ sudo chgrp root /etc/issue.net
|
|
Verify Group Ownership of Message of the Day Banner |
To properly set the group owner of /etc/motd, run the command:
$ sudo chgrp root /etc/motd
|
|
Verify ownership of System Login Banner |
To properly set the owner of /etc/issue, run the command:
$ sudo chown root /etc/issue
|
|
Verify ownership of System Login Banner for Remote Connections |
To properly set the owner of /etc/issue.net, run the command:
$ sudo chown root /etc/issue.net
|
|
Verify ownership of Message of the Day Banner |
To properly set the owner of /etc/motd, run the command:
$ sudo chown root /etc/motd
|
|
Verify permissions on System Login Banner |
To properly set the permissions of /etc/issue, run the command:
$ sudo chmod 0644 /etc/issue
|
|
Verify permissions on System Login Banner for Remote Connections |
To properly set the permissions of /etc/issue.net, run the command:
$ sudo chmod 0644 /etc/issue.net
|
|
Verify permissions on Message of the Day Banner |
To properly set the permissions of /etc/motd, run the command:
$ sudo chmod 0644 /etc/motd
|
|
Configure the Use of the pam_faillock.so Module in the /etc/pam.d/password-auth File. |
The pam_faillock.so module must be loaded in preauth in /etc/pam.d/password-auth. |
|
Configure the Use of the pam_faillock.so Module in the /etc/pam.d/system-auth File. |
The pam_faillock.so module must be loaded in preauth in /etc/pam.d/system-auth. |
|
Limit Password Reuse: password-auth |
Do not allow users to reuse recent passwords. This can be accomplished by using the
remember option for the pam_pwhistory PAM module.
On systems with newer versions of authselect, the pam_pwhistory PAM module
can be enabled via authselect feature:
authselect enable-feature with-pwhistory
Otherwise, it should be enabled using an authselect custom profile.
Newer systems also have the /etc/security/pwhistory.conf file for setting
pam_pwhistory module options. This file should be used whenever available.
Otherwise, the pam_pwhistory module options can be set in PAM files.
The value for remember option must be equal or greater than
|
|
Limit Password Reuse: system-auth |
Do not allow users to reuse recent passwords. This can be accomplished by using the
remember option for the pam_pwhistory PAM module.
On systems with newer versions of authselect, the pam_pwhistory PAM module
can be enabled via authselect feature:
authselect enable-feature with-pwhistory
Otherwise, it should be enabled using an authselect custom profile.
Newer systems also have the /etc/security/pwhistory.conf file for setting
pam_pwhistory module options. This file should be used whenever available.
Otherwise, the pam_pwhistory module options can be set in PAM files.
The value for remember option must be equal or greater than
|
|
Lock Accounts After Failed Password Attempts |
This 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.
Ensure that the file /etc/security/faillock.conf contains the following entry:
deny = <count>
Where count should be less than or equal to
and greater than 0.
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. |
|
Set Lockout Time for Failed Password Attempts |
This rule configures the system to lock out accounts during a specified time period after a
number of incorrect login attempts using pam_faillock.so.
Ensure that the file /etc/security/faillock.conf contains the following entry:
unlock_time=<interval-in-seconds> where
interval-in-seconds is 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. |
|
Ensure PAM Enforces Password Requirements - Minimum Different Categories |
The pam_pwquality module's minclass parameter controls
requirements for usage of different character classes, or types, of character
that must exist in a password before it is considered valid. For example,
setting this value to three (3) requires that any password must have characters
from at least three different categories in order to be approved. The default
value is zero (0), meaning there are no required classes. There are four
categories available:
* Upper-case characters
* Lower-case characters
* Digits
* Special characters (for example, punctuation)
Modify the minclass setting in /etc/security/pwquality.conf entry
to require
differing categories of characters when changing passwords. |
|
Ensure PAM Enforces Password Requirements - Minimum Length |
The pam_pwquality module's minlen parameter controls requirements for
minimum characters required in a password. Add minlen=
after pam_pwquality to set minimum password length requirements. |
|
Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted Per-Session |
To configure the number of retry prompts that are permitted per-session:
Edit the pam_pwquality.so statement in
/etc/pam.d/system-auth to show
retry=
, or a lower value if site
policy is more restrictive. The DoD requirement is a maximum of 3 prompts
per session. |
|
Set Password Hashing Algorithm in /etc/login.defs |
In /etc/login.defs, add or update the following line to ensure the system will use
as the hashing algorithm:
ENCRYPT_METHOD
|
|
Set PAM''s Password Hashing Algorithm - password-auth |
The PAM system service can be configured to only store encrypted representations of passwords.
In /etc/pam.d/password-auth, the password section of the file controls which
PAM modules to execute during a password change.
Set the pam_unix.so module in the password section to include the option
password sufficient pam_unix.so
other arguments...
This will help ensure that new passwords for local users will be stored using the
algorithm. |
|
Set PAM''s Password Hashing Algorithm |
The 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 to execute during a password change.
Set the pam_unix.so module in the password section to include the option
password sufficient pam_unix.so
other arguments...
This will help ensure that new passwords for local users will be stored using the
algorithm. |
|
Ensure All Accounts on the System Have Unique User IDs |
Change user IDs (UIDs), or delete accounts, so each has a unique name. |
|
Ensure All Groups on the System Have Unique Group ID |
Change the group name or delete groups, so each has a unique id. |
|
Ensure All Groups on the System Have Unique Group Names |
Change the group name or delete groups, so each has a unique name. |
|
Set Account Expiration Following Inactivity |
To specify the number of days after a password expires (which
signifies inactivity) until an account is permanently disabled, add or correct
the following line in /etc/default/useradd:
INACTIVE=
If a password is currently on the verge of expiration, then
useradd man page for more information. |
|
Ensure All Accounts on the System Have Unique Names |
Ensure accounts on the system have unique names.
To ensure all accounts have unique names, run the following command:
$ sudo getent passwd | awk -F: '{ print $1}' | uniq -d
If a username is returned, change or delete the username. |
|
Set Password Maximum Age |
To specify password maximum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MAX_DAYS
A value of 180 days is sufficient for many environments.
The DoD requirement is 60.
The profile requirement is |
|
Set Password Minimum Age |
To specify password minimum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MIN_DAYS
A value of 1 day is considered sufficient for many
environments. The DoD requirement is 1.
The profile requirement is |
|
Set Existing Passwords Maximum Age |
Configure non-compliant accounts to enforce a -day maximum password lifetime
restriction by running the following command:
$ sudo chage -M
USER
|
|
Set Existing Passwords Minimum Age |
Configure non-compliant accounts to enforce a 24 hours/1 day minimum password
lifetime by running the following command:
$ sudo chage -m 1 USER
|
|
Set Existing Passwords Warning Age |
To configure how many days prior to password expiration that a warning will be issued to
users, run the command:
$ sudo chage --warndays
USER
The DoD requirement is 7, and CIS recommendation is no less than 7 days.
This profile requirement is |
|
Set Password Warning Age |
To specify how many days prior to password
expiration that a warning will be issued to users,
edit the file /etc/login.defs and add or correct
the following line:
PASS_WARN_AGE
The DoD requirement is 7.
The profile requirement is |
|
Set existing passwords a period of inactivity before they been locked |
Configure user accounts that have been inactive for over a given period of time
to be automatically disabled by running the following command:
$ sudo chage --inactive 30USER
|
|
Verify All Account Password Hashes are Shadowed |
If any password hashes are stored in /etc/passwd (in the second field,
instead of an x or *), the cause of this misconfiguration should be
investigated. The account should have its password reset and the hash should be
properly stored, or the account should be deleted entirely. |
|
Ensure all users last password change date is in the past |
All users should have a password change date in the past. |
|
All GIDs referenced in /etc/passwd must be defined in /etc/group |
Add a group to the system for each GID referenced without a corresponding group. |
|
Ensure There Are No Accounts With Blank or Null Passwords |
Check the "/etc/shadow" file for blank passwords with the
following command:
$ sudo awk -F: '!$2 {print $1}' /etc/shadow
If the command returns any results, this is a finding.
Configure all accounts on the system to have a password or lock
the account with the following commands:
Perform a password reset:
$ sudo passwd [username]
Lock an account:
$ sudo passwd -l [username]
|
|
Verify No .forward Files Exist |
The .forward file specifies an email address to forward the user's mail to. |
|
Verify Only Root Has UID 0 |
If any account other than root has a UID of 0, this misconfiguration should
be investigated and the accounts other than root should be removed or have
their UID changed.
If the account is associated with system commands or applications the UID
should be changed to one greater than "0" but less than "1000."
Otherwise assign a UID greater than "1000" that has not already been
assigned. |
|
Verify Root Has A Primary GID 0 |
The root user should have a primary group of 0. |
|
Ensure the Group Used by pam_wheel.so Module Exists on System and is Empty |
Ensure that the group var_pam_wheel_group_for_su variable and used as value for the pam_wheel.so
group option exists and has no members. This empty group used by
pam_wheel.so in /etc/pam.d/su ensures that no user can run commands with
altered privileges through the su command. |
|
Ensure Authentication Required for Single User Mode |
Single user mode is used for recovery when the system detects an
issue during boot or by manual selection from the bootloader. |
|
Ensure that System Accounts Are Locked |
Some accounts are not associated with a human user of the system, and exist to perform some
administrative functions. An attacker should not be able to log into these accounts.
System accounts are those user accounts with a user ID less than 1000.
If any system account other than root, halt, sync, shutdown
and nfsnobody has an unlocked password, disable it with the command:
$ sudo usermod -L account
|
|
Ensure that System Accounts Do Not Run a Shell Upon Login |
Some accounts are not associated with a human user of the system, and exist to perform some
administrative functions. Should an attacker be able to log into these accounts, they should
not be granted access to a shell.
The login shell for each local account is stored in the last field of each line in
/etc/passwd. System accounts are those user accounts with a user ID less than
1000. The user ID is stored in the third field. If any system account
other than root has a login shell, disable it with the command:
$ sudo usermod -s /sbin/nologin account
|
|
Enforce Usage of pam_wheel with Group Parameter for su Authentication |
To ensure that only users who are members of the group set in the group option of
pam_wheel.so module can run commands with altered privileges through the su
command, make sure that the following line exists in the file /etc/pam.d/su:
auth required pam_wheel.so use_uid group=
|
|
Set Interactive Session Timeout |
Setting 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, e.g.
/etc/profile.d/tmout.sh should read as follows:
typeset -xr TMOUT=
or
declare -xr TMOUT=
Using the typeset keyword is preferred for wider compatibility with ksh and other shells. |
|
User Initialization Files Must Be Group-Owned By The Primary Group |
Change the group owner of interactive users files to the group found
in /etc/passwd for the user. To change the group owner of a local
interactive user home directory, use the following command:
$ sudo chgrp USER_GROUP /home/USER/.INIT_FILE
This rule ensures every initialization file related to an interactive user
is group-owned by an interactive user. |
|
User Initialization Files Must Be Owned By the Primary User |
Set the owner of the user initialization files for interactive users to
the primary owner with the following command:
$ sudo chown USER /home/USER/.*
This rule ensures every initialization file related to an interactive user
is owned by an interactive user. |
|
All Interactive Users Home Directories Must Exist |
Create home directories to all local interactive users that currently do not
have a home directory assigned. Use the following commands to create the user
home directory assigned in /etc/passwd:
$ sudo mkdir /home/USER
|
|
Ensure users' .netrc Files are not group or world accessible |
While the system administrator can establish secure permissions for users' .netrc files, the
users can easily override these.
This rule ensures every .netrc file or directory under the home directory related
to an interactive user is not group or world accessible |
|
All Interactive User Home Directories Must Be Group-Owned By The Primary Group |
Change the group owner of interactive users home directory to the
group found in /etc/passwd. To change the group owner of
interactive users home directory, use the following command:
$ sudo chgrp USER_GROUP /home/USER
This rule ensures every home directory related to an interactive user is
group-owned by an interactive user. It also ensures that interactive users
are group-owners of one and only one home directory. |
|
All Interactive User Home Directories Must Be Owned By The Primary User |
Change the owner of interactive users home directories to that correct
owner. To change the owner of a interactive users home directory, use
the following command:
$ sudo chown USER /home/USER
This rule ensures every home directory related to an interactive user is
owned by an interactive user. It also ensures that interactive users are
owners of one and only one home directory. |
|
Ensure All User Initialization Files Have Mode 0740 Or Less Permissive |
Set the mode of the user initialization files to 0740 with the
following command:
$ sudo chmod 0740 /home/USER/.INIT_FILE
|
|
All Interactive User Home Directories Must Have mode 0750 Or Less Permissive |
Change the mode of interactive users home directories to 0750. To
change the mode of interactive users home directory, use the
following command:
$ sudo chmod 0750 /home/USER
|
|
Ensure that Root's Path Does Not Include World or Group-Writable Directories |
For each element in root's path, run:
# ls -ld DIR
and ensure that write permissions are disabled for group and
other. |
|
Ensure that Root's Path Does Not Include Relative Paths or Null Directories |
Ensure that none of the directories in root's path is equal to a single
. character, or
that it contains any instances that lead to relative path traversal, such as
.. or beginning a path without the slash (/) character.
Also ensure that there are no "empty" elements in the path, such as in these examples:
PATH=:/bin
PATH=/bin:
PATH=/bin::/sbin
These empty elements have the same effect as a single . character. |
|
Ensure the Default Bash Umask is Set Correctly |
To ensure the default umask for users of the Bash shell is set properly,
add or correct the umask setting in /etc/bashrc to read
as follows:
umask
|
|
Ensure the Default Umask is Set Correctly in login.defs |
To ensure the default umask controlled by /etc/login.defs is set properly,
add or correct the UMASK setting in /etc/login.defs to read as follows:
UMASK
|
|
Ensure the Default Umask is Set Correctly in /etc/profile |
To ensure the default umask controlled by /etc/profile is set properly,
add or correct the umask setting in /etc/profile to read as follows:
umask
Note that /etc/profile also reads scrips within /etc/profile.d directory.
These scripts are also valid files to set umask value. Therefore, they should also be
considered during the check and properly remediated, if necessary. |
|
Verify /boot/grub2/grub.cfg Group Ownership |
The file /boot/grub2/grub.cfg should
be group-owned by the root group to prevent
destruction or modification of the file.
To properly set the group owner of /boot/grub2/grub.cfg, run the command:
$ sudo chgrp root /boot/grub2/grub.cfg
|
|
Verify /boot/grub2/user.cfg Group Ownership |
The file /boot/grub2/user.cfg should be group-owned by the root
group to prevent reading or modification of the file.
To properly set the group owner of /boot/grub2/user.cfg, run the command:
$ sudo chgrp root /boot/grub2/user.cfg
|
|
Verify /boot/grub2/grub.cfg User Ownership |
The file /boot/grub2/grub.cfg should
be owned by the root user to prevent destruction
or modification of the file.
To properly set the owner of /boot/grub2/grub.cfg, run the command:
$ sudo chown root /boot/grub2/grub.cfg
|
|
Verify /boot/grub2/user.cfg User Ownership |
The file /boot/grub2/user.cfg should be owned by the root
user to prevent reading or modification of the file.
To properly set the owner of /boot/grub2/user.cfg, run the command:
$ sudo chown root /boot/grub2/user.cfg
|
|
Verify /boot/grub2/grub.cfg Permissions |
File permissions for /boot/grub2/grub.cfg should be set to 600.
To properly set the permissions of /boot/grub2/grub.cfg, run the command:
$ sudo chmod 600 /boot/grub2/grub.cfg
|
|
Verify /boot/grub2/user.cfg Permissions |
File permissions for /boot/grub2/user.cfg should be set to 600.
To properly set the permissions of /boot/grub2/user.cfg, run the command:
$ sudo chmod 600 /boot/grub2/user.cfg
|
|
Ensure rsyslog is Installed |
Rsyslog is installed by default. The rsyslog package can be installed with the following command: $ sudo dnf install rsyslog
|
|
Ensure rsyslog Default File Permissions Configured |
rsyslog will create logfiles that do not already exist on the system.
This settings controls what permissions will be applied to these newly
created files. |
|
Ensure Log Files Are Owned By Appropriate Group |
The group-owner of all log files written by
rsyslog should be root.
These log files are determined by the second part of each Rule line in
/etc/rsyslog.conf and typically all appear in /var/log.
For each log file LOGFILE referenced in /etc/rsyslog.conf,
run the following command to inspect the file's group owner:
$ ls -l LOGFILE
If the owner is not root,
run the following command to
correct this:
$ sudo chgrp root LOGFILE
|
|
Ensure Log Files Are Owned By Appropriate User |
The owner of all log files written by
rsyslog should be
root.
These log files are determined by the second part of each Rule line in
/etc/rsyslog.conf and typically all appear in /var/log.
For each log file LOGFILE referenced in /etc/rsyslog.conf,
run the following command to inspect the file's owner:
$ ls -l LOGFILE
If the owner is not
root,
run the following command to
correct this:
$ sudo chown root LOGFILE
|
|
Ensure System Log Files Have Correct Permissions |
The file permissions for all log files written by rsyslog should
be set to 640, or more restrictive. These log files are determined by the
second part of each Rule line in /etc/rsyslog.conf and typically
all appear in /var/log. For each log file LOGFILE
referenced in /etc/rsyslog.conf, run the following command to
inspect the file's permissions:
$ ls -l LOGFILE
If the permissions are not 640 or more restrictive, run the following
command to correct this:
$ sudo chmod 640 LOGFILE
" |
|
Enable systemd-journald Service |
The systemd-journald service is an essential component of
systemd.
The systemd-journald service can be enabled with the following command:
$ sudo systemctl enable systemd-journald.service
|
|
Ensure journald is configured to compress large log files |
The journald system can compress large log files to avoid fill the system disk. |
|
Ensure journald is configured to send logs to rsyslog |
Data from journald may be stored in volatile memory or persisted locally.
Utilities exist to accept remote export of journald logs. |
|
Ensure journald is configured to write log files to persistent disk |
The journald system may store log files in volatile memory or locally on disk.
If the logs are only stored in volatile memory they will we lost upon reboot. |
|
Disable systemd-journal-remote Socket |
Journald supports the ability to receive messages from remote hosts,
thus acting as a log server. Clients should not receive data from
other hosts.
NOTE:
The same package, systemd-journal-remote , is used for both sending
logs to remote hosts and receiving incoming logs.
With regards to receiving logs, there are two Systemd unit files;
systemd-journal-remote.socket and systemd-journal-remote.service. |
|
Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server |
The rsyslog daemon should not accept remote messages unless the system acts as a log
server. To ensure that it is not listening on the network, ensure any of the following lines
are not found in rsyslog configuration files.
If using legacy syntax:
$ModLoad imtcp
$InputTCPServerRun port
$ModLoad imudp
$UDPServerRun port
$ModLoad imrelp
$InputRELPServerRun port
If using RainerScript syntax:
module(load="imtcp")
module(load="imudp")
input(type="imtcp" port="514")
input(type="imudp" port="514")
|
|
Ensure Logs Sent To Remote Host |
To configure rsyslog to send logs to a remote log server,
open /etc/rsyslog.conf and read and understand the last section of the file,
which describes the multiple directives necessary to activate remote
logging.
Along with these other directives, the system can be configured
to forward its logs to a particular log server by
adding or correcting one of the following lines,
substituting
To use UDP for log message delivery:
*.* @
To use TCP for log message delivery:
*.* @@
To use RELP for log message delivery:
*.* :omrelp:
There must be a resolvable DNS CNAME or Alias record set to "" for logs to be sent correctly to the centralized logging utility. |
|
Install firewalld Package |
The firewalld package can be installed with the following command:
$ sudo dnf install firewalld
|
|
Verify firewalld Enabled |
The firewalld service can be enabled with the following command:
$ sudo systemctl enable firewalld.service
|
|
Configure Firewalld to Restrict Loopback Traffic |
Configure firewalld to restrict loopback traffic to the lo interface.
The loopback traffic must be trusted by assigning the lo interface to the
firewalld
trusted zone. However, the loopback traffic must be restricted
to the loopback interface as an anti-spoofing measure.
To configure firewalld to restrict loopback traffic to the lo interface,
run the following commands:
sudo firewall-cmd --permanent --zone=trusted --add-rich-rule='rule family=ipv4 source address="127.0.0.1" destination not address="127.0.0.1" drop'
sudo firewall-cmd --permanent --zone=trusted --add-rich-rule='rule family=ipv6 source address="::1" destination not address="::1" drop'
To ensure firewalld settings are applied in runtime, run the following command:
firewall-cmd --reload
|
|
Configure Firewalld to Trust Loopback Traffic |
Assign loopback interface to the firewalld
trusted zone in order to
explicitly allow the loopback traffic in the system.
To configure firewalld to trust loopback traffic, run the following command:
sudo firewall-cmd --permanent --zone=trusted --add-interface=lo
To ensure firewalld settings are applied in runtime, run the following command:
firewall-cmd --reload
|
|
Set Default firewalld Zone for Incoming Packets |
To set the default zone to drop for
the built-in default zone which processes incoming IPv4 and IPv6 packets,
modify the following line in
/etc/firewalld/firewalld.conf to be:
DefaultZone=drop
|
|
Configure Accepting Router Advertisements on All IPv6 Interfaces |
To set the runtime status of the net.ipv6.conf.all.accept_ra kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_ra=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 = 0
|
|
Disable Accepting ICMP Redirects for All IPv6 Interfaces |
To 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
|
|
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv6 Interfaces |
To 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
|
|
Disable Kernel Parameter for IPv6 Forwarding |
To set the runtime status of the net.ipv6.conf.all.forwarding kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.forwarding=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.forwarding = 0
|
|
Disable Accepting Router Advertisements on all IPv6 Interfaces by Default |
To set the runtime status of the net.ipv6.conf.default.accept_ra kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_ra=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 = 0
|
|
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv6 Interfaces |
To 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
|
|
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv6 Interfaces by Default |
To 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
|
|
Disable Accepting ICMP Redirects for All IPv4 Interfaces |
To 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
|
|
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv4 Interfaces |
To 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
|
|
Enable Kernel Parameter to Log Martian Packets on all IPv4 Interfaces |
To set the runtime status of the net.ipv4.conf.all.log_martians kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.log_martians=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.log_martians = 1
|
|
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces |
To 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
|
|
Disable Kernel Parameter for Accepting Secure ICMP Redirects on all IPv4 Interfaces |
To 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
|
|
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces |
To 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
|
|
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv4 Interfaces by Default |
To 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
|
|
Enable Kernel Paremeter to Log Martian Packets on all IPv4 Interfaces by Default |
To set the runtime status of the net.ipv4.conf.default.log_martians kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.log_martians=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.log_martians = 1
|
|
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces by Default |
To 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
|
|
Configure Kernel Parameter for Accepting Secure Redirects By Default |
To 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
|
|
Enable Kernel Parameter to Ignore ICMP Broadcast Echo Requests on IPv4 Interfaces |
To set the runtime status of the net.ipv4.icmp_echo_ignore_broadcasts kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=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_echo_ignore_broadcasts = 1
|
|
Enable Kernel Parameter to Ignore Bogus ICMP Error Responses on IPv4 Interfaces |
To 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
|
|
Enable Kernel Parameter to Use TCP Syncookies on Network Interfaces |
To 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
|
|
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces |
To 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
|
|
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default |
To 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
|
|
Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces |
To 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
|
|
Install nftables Package |
nftables provides a new in-kernel packet classification framework that is based on a
network-specific Virtual Machine (VM) and a new nft userspace command line tool.
nftables reuses the existing Netfilter subsystems such as the existing hook infrastructure,
the connection tracking system, NAT, userspace queuing and logging subsystem.
The nftables package can be installed with the following command:
$ sudo dnf install nftables
|
|
Verify nftables Service is Disabled |
nftables is a subsystem of the Linux kernel providing filtering and classification of network
packets/datagrams/frames and is the successor to iptables.
The nftables service can be disabled with the following command:
systemctl disable nftables
|
|
Ensure a Table Exists for Nftables |
Tables in nftables hold chains. Each table only has one address family and only applies
to packets of this family. Tables can have one of six families. |
|
Disable DCCP Support |
The Datagram Congestion Control Protocol (DCCP) is a
relatively new transport layer protocol, designed to support
streaming media and telephony.
To configure the system to prevent the dccp
kernel module from being loaded, add the following line to the file /etc/modprobe.d/dccp.conf:
install dccp /bin/false
|
|
Disable RDS Support |
The Reliable Datagram Sockets (RDS) protocol is a transport
layer protocol designed to provide reliable high-bandwidth,
low-latency communications between nodes in a cluster.
To configure the system to prevent the rds
kernel module from being loaded, add the following line to the file /etc/modprobe.d/rds.conf:
install rds /bin/false
|
|
Disable SCTP Support |
The Stream Control Transmission Protocol (SCTP) is a
transport layer protocol, designed to support the idea of
message-oriented communication, with several streams of messages
within one connection.
To configure the system to prevent the sctp
kernel module from being loaded, add the following line to the file /etc/modprobe.d/sctp.conf:
install sctp /bin/false
|
|
Disable TIPC Support |
The Transparent Inter-Process Communication (TIPC) protocol
is designed to provide communications between nodes in a
cluster.
To configure the system to prevent the tipc
kernel module from being loaded, add the following line to the file /etc/modprobe.d/tipc.conf:
install tipc /bin/false
|
|
Verify that All World-Writable Directories Have Sticky Bits Set |
When 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
|
|
Ensure No World-Writable Files Exist |
It 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. |
|
Ensure All Files Are Owned by a Group |
If any file is not group-owned by a group present in /etc/group, the cause of the lack of
group-ownership must be investigated. Following this, those files should be deleted or
assigned to an appropriate group.
Locate the mount points related to local devices by the following command:
$ findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)
For all mount points listed by the previous command, it is necessary to search for files which
do not belong to a valid group using the following command:
$ sudo find MOUNTPOINT -xdev -nogroup 2>/dev/null
|
|
Ensure All Files Are Owned by a User |
If 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.
Locate the mount points related to local devices by the following command:
$ findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)
For all mount points listed by the previous command, it is necessary to search for files which
do not belong to a valid user using the following command:
$ sudo find MOUNTPOINT -xdev -nouser 2>/dev/null
|
|
Verify Group Who Owns Backup group File |
To properly set the group owner of /etc/group-, run the command: $ sudo chgrp root /etc/group-
|
|
Verify Group Who Owns Backup gshadow File |
To properly set the group owner of /etc/gshadow-, run the command: $ sudo chgrp root /etc/gshadow-
|
|
Verify Group Who Owns Backup passwd File |
To properly set the group owner of /etc/passwd-, run the command: $ sudo chgrp root /etc/passwd-
|
|
Verify User Who Owns Backup shadow File |
To properly set the group owner of /etc/shadow-, run the command: $ sudo chgrp root /etc/shadow-
|
|
Verify Group Who Owns group File |
To properly set the group owner of /etc/group, run the command: $ sudo chgrp root /etc/group
|
|
Verify Group Who Owns gshadow File |
To properly set the group owner of /etc/gshadow, run the command: $ sudo chgrp root /etc/gshadow
|
|
Verify Group Who Owns passwd File |
To properly set the group owner of /etc/passwd, run the command: $ sudo chgrp root /etc/passwd
|
|
Verify Group Who Owns shadow File |
To properly set the group owner of /etc/shadow, run the command: $ sudo chgrp root /etc/shadow
|
|
Verify User Who Owns Backup group File |
To properly set the owner of /etc/group-, run the command: $ sudo chown root /etc/group-
|
|
Verify User Who Owns Backup gshadow File |
To properly set the owner of /etc/gshadow-, run the command: $ sudo chown root /etc/gshadow-
|
|
Verify User Who Owns Backup passwd File |
To properly set the owner of /etc/passwd-, run the command: $ sudo chown root /etc/passwd-
|
|
Verify Group Who Owns Backup shadow File |
To properly set the owner of /etc/shadow-, run the command: $ sudo chown root /etc/shadow-
|
|
Verify User Who Owns group File |
To properly set the owner of /etc/group, run the command: $ sudo chown root /etc/group
|
|
Verify User Who Owns gshadow File |
To properly set the owner of /etc/gshadow, run the command: $ sudo chown root /etc/gshadow
|
|
Verify User Who Owns passwd File |
To properly set the owner of /etc/passwd, run the command: $ sudo chown root /etc/passwd
|
|
Verify User Who Owns shadow File |
To properly set the owner of /etc/shadow, run the command: $ sudo chown root /etc/shadow
|
|
Verify Permissions on Backup group File |
To properly set the permissions of /etc/group-, run the command:
$ sudo chmod 0644 /etc/group-
|
|
Verify Permissions on Backup gshadow File |
To properly set the permissions of /etc/gshadow-, run the command:
$ sudo chmod 0000 /etc/gshadow-
|
|
Verify Permissions on Backup passwd File |
To properly set the permissions of /etc/passwd-, run the command:
$ sudo chmod 0644 /etc/passwd-
|
|
Verify Permissions on Backup shadow File |
To properly set the permissions of /etc/shadow-, run the command:
$ sudo chmod 0000 /etc/shadow-
|
|
Verify Permissions on group File |
To properly set the permissions of /etc/group, run the command:
$ sudo chmod 0644 /etc/group
|
|
Verify Permissions on gshadow File |
To properly set the permissions of /etc/gshadow, run the command:
$ sudo chmod 0000 /etc/gshadow
|
|
Verify Permissions on passwd File |
To properly set the permissions of /etc/passwd, run the command:
$ sudo chmod 0644 /etc/passwd
|
|
Verify Permissions on shadow File |
To properly set the permissions of /etc/shadow, run the command:
$ sudo chmod 0000 /etc/shadow
|
|
Verify that audit tools are owned by group root |
The Amazon Linux 2023 operating system audit tools must have the proper
ownership configured to protected against unauthorized access.
Verify it by running the following command:
$ stat -c "%n %G" /sbin/auditctl /sbin/aureport /sbin/ausearch /sbin/autrace /sbin/auditd /sbin/audispd /sbin/augenrules
/sbin/auditctl root
/sbin/aureport root
/sbin/ausearch root
/sbin/autrace root
/sbin/auditd root
/sbin/audispd root
/sbin/augenrules root
Audit tools needed to successfully view and manipulate audit information
system activity and records. Audit tools include custom queries and report
generators |
|
Verify that audit tools are owned by root |
The Amazon Linux 2023 operating system audit tools must have the proper
ownership configured to protected against unauthorized access.
Verify it by running the following command:
$ stat -c "%n %U" /sbin/auditctl /sbin/aureport /sbin/ausearch /sbin/autrace /sbin/auditd /sbin/audispd /sbin/augenrules
/sbin/auditctl root
/sbin/aureport root
/sbin/ausearch root
/sbin/autrace root
/sbin/auditd root
/sbin/audispd root
/sbin/augenrules root
Audit tools needed to successfully view and manipulate audit information
system activity and records. Audit tools include custom queries and report
generators |
|
Verify that audit tools Have Mode 0755 or less |
The Amazon Linux 2023 operating system audit tools must have the proper
permissions configured to protected against unauthorized access.
Verify it by running the following command:
$ stat -c "%n %a" /sbin/auditctl /sbin/aureport /sbin/ausearch /sbin/autrace /sbin/auditd /sbin/audispd /sbin/augenrules
/sbin/auditctl 755
/sbin/aureport 755
/sbin/ausearch 755
/sbin/autrace 755
/sbin/auditd 755
/sbin/audispd 755
/sbin/augenrules 755
Audit tools needed to successfully view and manipulate audit information
system activity and records. Audit tools include custom queries and report
generators |
|
Disable Mounting of cramfs |
To configure the system to prevent the cramfs
kernel module from being loaded, add the following line to the file /etc/modprobe.d/cramfs.conf:
install cramfs /bin/false
This effectively prevents usage of this uncommon filesystem.
The cramfs filesystem type is a compressed read-only
Linux filesystem embedded in small footprint systems. A
cramfs image can be used without having to first
decompress the image. |
|
Disable Mounting of freevxfs |
To configure the system to prevent the freevxfs
kernel module from being loaded, add the following line to the file /etc/modprobe.d/freevxfs.conf:
install freevxfs /bin/false
This effectively prevents usage of this uncommon filesystem. |
|
Disable Mounting of hfs |
To configure the system to prevent the hfs
kernel module from being loaded, add the following line to the file /etc/modprobe.d/hfs.conf:
install hfs /bin/false
This effectively prevents usage of this uncommon filesystem. |
|
Disable Mounting of hfsplus |
To configure the system to prevent the hfsplus
kernel module from being loaded, add the following line to the file /etc/modprobe.d/hfsplus.conf:
install hfsplus /bin/false
This effectively prevents usage of this uncommon filesystem. |
|
Disable Mounting of jffs2 |
To configure the system to prevent the jffs2
kernel module from being loaded, add the following line to the file /etc/modprobe.d/jffs2.conf:
install jffs2 /bin/false
This effectively prevents usage of this uncommon filesystem. |
|
Disable Mounting of squashfs |
To configure the system to prevent the squashfs
kernel module from being loaded, add the following line to the file /etc/modprobe.d/squashfs.conf:
install squashfs /bin/false
This effectively prevents usage of this uncommon filesystem.
The squashfs filesystem type is a compressed read-only Linux
filesystem embedded in small footprint systems (similar to
cramfs). A squashfs image can be used without having
to first decompress the image. |
|
Disable Mounting of udf |
To configure the system to prevent the udf
kernel module from being loaded, add the following line to the file /etc/modprobe.d/udf.conf:
install udf /bin/false
This effectively prevents usage of this uncommon filesystem.
The udf filesystem type is the universal disk format
used to implement the ISO/IEC 13346 and ECMA-167 specifications.
This is an open vendor filesystem type for data storage on a broad
range of media. This filesystem type is neccessary to support
writing DVDs and newer optical disc formats. |
|
Disable Modprobe Loading of USB Storage Driver |
To prevent USB storage devices from being used, configure the kernel module loading system
to prevent automatic loading of the USB storage driver.
To configure the system to prevent the usb-storage
kernel module from being loaded, add the following line to the file /etc/modprobe.d/usb-storage.conf:
install usb-storage /bin/false
This will prevent the modprobe program from loading the usb-storage
module, but will not prevent an administrator (or another program) from using the
insmod program to load the module manually. |
|
Add nodev Option to /dev/shm |
The nodev mount option can be used to prevent creation of device
files in /dev/shm. Legitimate character and block devices should
not exist within temporary directories like /dev/shm.
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm. |
|
Add noexec Option to /dev/shm |
The noexec mount option can be used to prevent binaries
from being executed out of /dev/shm.
It can be dangerous to allow the execution of binaries
from world-writable temporary storage directories such as /dev/shm.
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm. |
|
Add nosuid Option to /dev/shm |
The nosuid mount option can be used to prevent execution
of setuid programs in /dev/shm. The SUID and SGID permissions should not
be required in these world-writable directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/dev/shm. |
|
Add nodev Option to /home |
The nodev mount option can be used to prevent device files from
being created in /home.
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
/home. |
|
Add nosuid Option to /home |
The 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. |
|
Add nodev Option to /tmp |
The nodev mount option can be used to prevent device files from
being created in /tmp. Legitimate character and block devices
should not exist within temporary directories like /tmp.
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/tmp. |
|
Add noexec Option to /tmp |
The 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. |
|
Add nosuid Option to /tmp |
The 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. |
|
Add nodev Option to /var/log/audit |
The nodev mount option can be used to prevent device files from
being created in /var/log/audit.
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
/var/log/audit. |
|
Add noexec Option to /var/log/audit |
The noexec mount option can be used to prevent binaries
from being executed out of /var/log/audit.
Add the noexec option to the fourth column of
/etc/fstab for the line which controls mounting of
/var/log/audit. |
|
Add nosuid Option to /var/log/audit |
The nosuid mount option can be used to prevent
execution of setuid programs in /var/log/audit. The SUID and SGID permissions
should not be required in directories containing audit log files.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/var/log/audit. |
|
Add nodev Option to /var/log |
The nodev mount option can be used to prevent device files from
being created in /var/log.
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
/var/log. |
|
Add noexec Option to /var/log |
The 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. |
|
Add nosuid Option to /var/log |
The 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. |
|
Add nodev Option to /var |
The nodev mount option can be used to prevent device files from
being created in /var.
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
/var. |
|
Add nosuid Option to /var |
The 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. |
|
Add nodev Option to /var/tmp |
The nodev mount option can be used to prevent device files from
being created in /var/tmp. Legitimate character and block devices
should not exist within temporary directories like /var/tmp.
Add the nodev option to the fourth column of
/etc/fstab for the line which controls mounting of
/var/tmp. |
|
Add noexec Option to /var/tmp |
The 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. |
|
Add nosuid Option to /var/tmp |
The 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. |
|
Restrict usage of ptrace to descendant processes |
To 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
|
|
Disable core dump backtraces |
The ProcessSizeMax option in [Coredump] section
of /etc/systemd/coredump.conf
specifies the maximum size in bytes of a core which will be processed.
Core dumps exceeding this size may be stored, but the backtrace will not
be generated. |
|
Disable storing core dump |
The Storage option in [Coredump] sectionof /etc/systemd/coredump.conf
can be set to none to disable storing core dumps permanently. |
|
Enable Randomized Layout of Virtual Address Space |
To 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
|
|
Install libselinux Package |
The libselinux package can be installed with the following command:
$ sudo dnf install libselinux
|
|
Uninstall mcstrans Package |
The mcstransd daemon provides category label information
to client processes requesting information. The label translations are defined
in /etc/selinux/targeted/setrans.conf.
The mcstrans package can be removed with the following command:
$ sudo dnf remove mcstrans
|
|
Uninstall setroubleshoot Package |
The SETroubleshoot service notifies desktop users of SELinux
denials. The service provides information around configuration errors,
unauthorized intrusions, and other potential errors.
The setroubleshoot package can be removed with the following command:
$ sudo dnf remove setroubleshoot
|
|
Ensure SELinux Not Disabled in /etc/default/grub |
SELinux can be disabled at boot time by an argument in
/etc/default/grub.
Remove any instances of selinux=0 from the kernel arguments in that
file to prevent SELinux from being disabled at boot. |
|
Ensure No Daemons are Unconfined by SELinux |
Daemons for which the SELinux policy does not contain rules will inherit the
context of the parent process. Because daemons are launched during
startup and descend from the init process, they inherit the unconfined_service_t context.
To check for unconfined daemons, run the following command:
$ sudo ps -eZ | grep "unconfined_service_t"
It should produce no output in a well-configured system. |
|
Ensure SELinux is Not Disabled |
The SELinux state should be set to enforcing or permissive at system boot
time. In the file /etc/selinux/config, add or correct the following line to configure
the system to boot into enforcing or permissive mode:
SELINUX=enforcing
OR
SELINUX=permissive
|
|
Configure SELinux Policy |
The SELinux targeted policy is appropriate for
general-purpose desktops and servers, as well as systems in many other roles.
To configure the system to use this policy, add or correct the following line
in /etc/selinux/config:
SELINUXTYPE=
Other policies, such as mls, provide additional security labeling
and greater confinement but are not compatible with many general-purpose
use cases. |
|
Ensure SELinux State is Enforcing |
The SELinux state should be set to /etc/selinux/config, add or correct the
following line to configure the system to boot into enforcing mode:
SELINUX=
|
|
Uninstall avahi Server Package |
If the system does not need to have an Avahi server which implements
the DNS Service Discovery and Multicast DNS protocols,
the avahi-autoipd and avahi packages can be uninstalled. |
|
Enable cron Service |
The crond service is used to execute commands at
preconfigured times. It is required by almost all systems to perform necessary
maintenance tasks, such as notifying root of system activity.
The crond service can be enabled with the following command:
$ sudo systemctl enable crond.service
|
|
Verify Group Who Owns cron.d |
To properly set the group owner of /etc/cron.d, run the command:
$ sudo chgrp root /etc/cron.d
|
|
Verify Group Who Owns cron.daily |
To properly set the group owner of /etc/cron.daily, run the command:
$ sudo chgrp root /etc/cron.daily
|
|
Verify Group Who Owns cron.hourly |
To properly set the group owner of /etc/cron.hourly, run the command:
$ sudo chgrp root /etc/cron.hourly
|
|
Verify Group Who Owns cron.monthly |
To properly set the group owner of /etc/cron.monthly, run the command:
$ sudo chgrp root /etc/cron.monthly
|
|
Verify Group Who Owns cron.weekly |
To properly set the group owner of /etc/cron.weekly, run the command:
$ sudo chgrp root /etc/cron.weekly
|
|
Verify Group Who Owns Crontab |
To properly set the group owner of /etc/crontab, run the command:
$ sudo chgrp root /etc/crontab
|
|
Verify Owner on cron.d |
To properly set the owner of /etc/cron.d, run the command:
$ sudo chown root /etc/cron.d
|
|
Verify Owner on cron.daily |
To properly set the owner of /etc/cron.daily, run the command:
$ sudo chown root /etc/cron.daily
|
|
Verify Owner on cron.hourly |
To properly set the owner of /etc/cron.hourly, run the command:
$ sudo chown root /etc/cron.hourly
|
|
Verify Owner on cron.monthly |
To properly set the owner of /etc/cron.monthly, run the command:
$ sudo chown root /etc/cron.monthly
|
|
Verify Owner on cron.weekly |
To properly set the owner of /etc/cron.weekly, run the command:
$ sudo chown root /etc/cron.weekly
|
|
Verify Owner on crontab |
To properly set the owner of /etc/crontab, run the command:
$ sudo chown root /etc/crontab
|
|
Verify Permissions on cron.d |
To properly set the permissions of /etc/cron.d, run the command:
$ sudo chmod 0700 /etc/cron.d
|
|
Verify Permissions on cron.daily |
To properly set the permissions of /etc/cron.daily, run the command:
$ sudo chmod 0700 /etc/cron.daily
|
|
Verify Permissions on cron.hourly |
To properly set the permissions of /etc/cron.hourly, run the command:
$ sudo chmod 0700 /etc/cron.hourly
|
|
Verify Permissions on cron.monthly |
To properly set the permissions of /etc/cron.monthly, run the command:
$ sudo chmod 0700 /etc/cron.monthly
|
|
Verify Permissions on cron.weekly |
To properly set the permissions of /etc/cron.weekly, run the command:
$ sudo chmod 0700 /etc/cron.weekly
|
|
Verify Permissions on crontab |
To properly set the permissions of /etc/crontab, run the command:
$ sudo chmod 0600 /etc/crontab
|
|
Ensure that /etc/at.deny does not exist |
The file /etc/at.deny should not exist.
Use /etc/at.allow instead. |
|
Ensure that /etc/cron.allow exists |
The file /etc/cron.allow should exist and should be used instead
of /etc/cron.deny. |
|
Ensure that /etc/cron.deny does not exist |
The file /etc/cron.deny should not exist.
Use /etc/cron.allow instead. |
|
Verify Group Who Owns /etc/at.allow file |
If /etc/at.allow exists, it must be group-owned by root.
To properly set the group owner of /etc/at.allow, run the command:
$ sudo chgrp root /etc/at.allow
|
|
Verify Group Who Owns /etc/cron.allow file |
If /etc/cron.allow exists, it must be group-owned by root.
To properly set the group owner of /etc/cron.allow, run the command:
$ sudo chgrp root /etc/cron.allow
|
|
Verify User Who Owns /etc/at.allow file |
If /etc/at.allow exists, it must be owned by root.
To properly set the owner of /etc/at.allow, run the command:
$ sudo chown root /etc/at.allow
|
|
Verify User Who Owns /etc/cron.allow file |
If /etc/cron.allow exists, it must be owned by root.
To properly set the owner of /etc/cron.allow, run the command:
$ sudo chown root /etc/cron.allow
|
|
Verify Permissions on /etc/at.allow file |
If /etc/at.allow exists, it must have permissions 0640
or more restrictive.
To properly set the permissions of /etc/at.allow, run the command:
$ sudo chmod 0640 /etc/at.allow
|
|
Verify Permissions on /etc/cron.allow file |
If /etc/cron.allow exists, it must have permissions 0640
or more restrictive.
To properly set the permissions of /etc/cron.allow, run the command:
$ sudo chmod 0640 /etc/cron.allow
|
|
Uninstall DHCP Server Package |
If 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 dnf remove dhcp
|
|
Uninstall dnsmasq Package |
dnsmasq is a lightweight tool that provides DNS caching, DNS forwarding and
DHCP (Dynamic Host Configuration Protocol) services.
The dnsmasq package can be removed with the following command:
$ sudo dnf remove dnsmasq
|
|
Uninstall bind Package |
The named service is provided by the bind package.
The bind package can be removed with the following command:
$ sudo dnf remove bind
|
|
Remove ftp Package |
FTP (File Transfer Protocol) is a traditional and widely used standard tool for
transferring files between a server and clients over a network, especially where no
authentication is necessary (permits anonymous users to connect to a server).
The ftp package can be removed with the following command:
$ sudo dnf remove ftp
|
|
Uninstall vsftpd Package |
The vsftpd package can be removed with the following command: $ sudo dnf remove vsftpd
|
|
Uninstall httpd Package |
The httpd package can be removed with the following command:
$ sudo dnf remove httpd
|
|
Uninstall nginx Package |
The nginx package can be removed with the following command:
$ sudo dnf remove nginx
|
|
Uninstall cyrus-imapd Package |
The cyrus-imapd package can be removed with the following command:
$ sudo dnf remove cyrus-imapd
|
|
Uninstall dovecot Package |
The dovecot package can be removed with the following command:
$ sudo dnf remove dovecot
|
|
Ensure LDAP client is not installed |
The Lightweight Directory Access Protocol (LDAP) is a service that provides
a method for looking up information from a central database.
The openldap-clients package can be removed with the following command:
$ sudo dnf remove openldap-clients
|
|
Ensure Mail Transfer Agent is not Listening on any non-loopback Address |
Mail Transfer Agents (MTA), such as sendmail and Postfix, are used to
listen for incoming mail and transfer the messages to the appropriate
user or mail server. If the system is not intended to be a mail server,
it is recommended that the MTA be configured to only process local mail. |
|
Disable Postfix Network Listening |
Edit the file /etc/postfix/main.cf to ensure that only the following
inet_interfaces line appears:
inet_interfaces =
|
|
Disable rpcbind Service |
The rpcbind utility maps RPC services to the ports on which they listen.
RPC processes notify rpcbind when they start, registering the ports they
are listening on and the RPC program numbers they expect to serve. The
rpcbind service redirects the client to the proper port number so it can
communicate with the requested service. If the system does not require RPC
(such as for NFS servers) then this service should be disabled.
The rpcbind service can be disabled with the following command:
$ sudo systemctl mask --now rpcbind.service
|
|
Disable Network File System (nfs) |
The Network File System (NFS) service allows remote hosts to mount
and interact with shared filesystems on the local system. If the local system
is not designated as a NFS server then this service should be disabled.
The nfs-server service can be disabled with the following command:
$ sudo systemctl mask --now nfs-server.service
|
|
A remote time server for Chrony is configured |
Chrony is a daemon which implements the Network Time Protocol (NTP). It is designed
to synchronize system clocks across a variety of systems and use a source that is highly
accurate. More information on chrony can be found at
https://chrony-project.org/.
Chrony can be configured to be a client and/or a server.
Add or edit server or pool lines to /etc/chrony.conf as appropriate:
server <remote-server>
Multiple servers may be configured. |
|
Ensure that chronyd is running under chrony user account |
chrony is a daemon which implements the Network Time Protocol (NTP). It is designed to
synchronize system clocks across a variety of systems and use a source that is highly
accurate. More information on chrony can be found at
https://chrony-project.org/.
Chrony can be configured to be a client and/or a server.
To ensure that chronyd is running under chrony user account,
add or edit the
OPTIONS variable in /etc/sysconfig/chronyd to include -u chrony:
OPTIONS="-u chrony"
This recommendation only applies if chrony is in use on the system. |
|
Uninstall rsync Package |
The rsyncd service can be used to synchronize files between systems over network links.
The rsync package can be removed with the following command:
$ sudo dnf remove rsync
|
|
Remove Rsh Trust Files |
The files /etc/hosts.equiv and ~/.rhosts (in
each user's home directory) list remote hosts and users that are trusted by the
local system when using the rshd daemon.
To remove these files, run the following command to delete them from any
location:
$ sudo rm /etc/hosts.equiv
$ rm ~/.rhosts
|
|
Uninstall telnet-server Package |
The telnet-server package can be removed with the following command:
$ sudo dnf remove telnet-server
|
|
Remove telnet Clients |
The telnet client allows users to start connections to other systems via
the telnet protocol. |
|
Uninstall tftp-server Package |
The tftp-server package can be removed with the following command: $ sudo dnf remove tftp-server
|
|
Uninstall CUPS Package |
The cups package can be removed with the following command:
$ sudo dnf remove cups
|
|
Uninstall squid Package |
The squid package can be removed with the following command: $ sudo dnf remove squid
|
|
Uninstall Samba Package |
The samba package can be removed with the following command: $ sudo dnf remove samba
|
|
Uninstall net-snmp Package |
The net-snmp package provides the snmpd service.
The net-snmp package can be removed with the following command:
$ sudo dnf remove net-snmp
|
|
Disable snmpd Service |
The snmpd service can be disabled with the following command:
$ sudo systemctl mask --now snmpd.service
|
|
Verify Group Who Owns SSH Server config file |
To properly set the group owner of /etc/ssh/sshd_config, run the command:
$ sudo chgrp root /etc/ssh/sshd_config
|
|
Verify Group Ownership on SSH Server Private *_key Key Files |
SSH server private keys, files that match the /etc/ssh/*_key glob, must be
group-owned by ssh_keys group. |
|
Verify Group Ownership on SSH Server Public *.pub Key Files |
SSH server public keys, files that match the /etc/ssh/*.pub glob, must be
group-owned by root group. |
|
Verify Owner on SSH Server config file |
To properly set the owner of /etc/ssh/sshd_config, run the command:
$ sudo chown root /etc/ssh/sshd_config
|
|
Verify Ownership on SSH Server Private *_key Key Files |
SSH server private keys, files that match the /etc/ssh/*_key glob, must be owned
by root user. |
|
Verify Ownership on SSH Server Public *.pub Key Files |
SSH server public keys, files that match the /etc/ssh/*.pub glob, must be owned
by root user. |
|
Verify Permissions on SSH Server config file |
To properly set the permissions of /etc/ssh/sshd_config, run the command:
$ sudo chmod 0600 /etc/ssh/sshd_config
|
|
Verify Permissions on SSH Server Private *_key Key Files |
SSH 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. |
|
Verify Permissions on SSH Server Public *.pub Key Files |
To properly set the permissions of /etc/ssh/*.pub, run the command: $ sudo chmod 0644 /etc/ssh/*.pub
|
|
Set SSH Client Alive Count Max |
The 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. |
|
Set SSH Client Alive Interval |
SSH 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
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. |
|
Disable Host-Based Authentication |
SSH's cryptographic host-based authentication is
more secure than .rhosts authentication. However, it is
not recommended that hosts unilaterally trust one another, even
within an organization.
The default SSH configuration disables host-based authentication. The appropriate
configuration is used if no value is set for HostbasedAuthentication.
To explicitly disable host-based authentication, add or correct the
following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf:
HostbasedAuthentication no
|
|
Disable SSH Access via Empty Passwords |
Disallow SSH login with empty passwords.
The default SSH configuration disables logins with empty passwords. The appropriate
configuration is used if no value is set for PermitEmptyPasswords.
To explicitly disallow SSH login from accounts with empty passwords,
add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf:
PermitEmptyPasswords no
Any accounts with empty passwords should be disabled immediately, and PAM configuration
should prevent users from being able to assign themselves empty passwords. |
|
Disable SSH Support for .rhosts Files |
SSH can emulate the behavior of the obsolete rsh
command in allowing users to enable insecure access to their
accounts via .rhosts files.
The default SSH configuration disables support for .rhosts. The appropriate
configuration is used if no value is set for IgnoreRhosts.
To explicitly disable support for .rhosts files, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf:
IgnoreRhosts yes
|
|
Disable SSH Root Login |
The root user should never be allowed to login to a
system directly over a network.
To disable root login via SSH, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf:
PermitRootLogin no
|
|
Disable SSH TCP Forwarding |
The AllowTcpForwarding parameter specifies whether TCP forwarding is permitted.
To disable TCP forwarding, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf:
AllowTcpForwarding no
|
|
Disable X11 Forwarding |
The X11Forwarding parameter provides the ability to tunnel X11 traffic
through the connection to enable remote graphic connections.
SSH has the capability to encrypt remote X11 connections when SSH's
X11Forwarding option is enabled.
The default SSH configuration disables X11Forwarding. The appropriate
configuration is used if no value is set for X11Forwarding.
To explicitly disable X11 Forwarding, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf:
X11Forwarding no
|
|
Do Not Allow SSH Environment Options |
Ensure that users are not able to override environment variables of the SSH daemon.
The default SSH configuration disables environment processing. The appropriate
configuration is used if no value is set for PermitUserEnvironment.
To explicitly disable Environment options, add or correct the following
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf:
PermitUserEnvironment no
|
|
Enable PAM |
UsePAM Enables the Pluggable Authentication Module interface. If set to “yes” this will
enable PAM authentication using ChallengeResponseAuthentication and
PasswordAuthentication in addition to PAM account and session module processing for all
authentication types.
To enable PAM authentication, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf:
UsePAM yes
|
|
Enable SSH Warning Banner |
To enable the warning banner and ensure it is consistent
across the system, add or correct the following line in
/etc/ssh/sshd_config:
Banner /etc/issue.net
Another section contains information on how to create an
appropriate system-wide warning banner. |
|
Limit Users' SSH Access |
By default, the SSH configuration allows any user with an account
to access the system. There are several options available to limit
which users and group can access the system via SSH. It is
recommended that at least one of the following options be leveraged:
- AllowUsers variable gives the system administrator the option of
allowing specific users to ssh into the system. The list consists of
space separated user names. Numeric user IDs are not recognized with
this variable. If a system administrator wants to restrict user
access further by specifically allowing a user's access only from a
particular host, the entry can be specified in the form of user@host.
- AllowGroups variable gives the system administrator the option of
allowing specific groups of users to ssh into the system. The list
consists of space separated group names. Numeric group IDs are not
recognized with this variable.
- DenyUsers variable gives the system administrator the option of
denying specific users to ssh into the system. The list consists of
space separated user names. Numeric user IDs are not recognized with
this variable. If a system administrator wants to restrict user
access further by specifically denying a user's access from a
particular host, the entry can be specified in the form of user@host.
- DenyGroups variable gives the system administrator the option of
denying specific groups of users to ssh into the system. The list
consists of space separated group names. Numeric group IDs are not
recognized with this variable. |
|
Ensure SSH LoginGraceTime is configured |
The LoginGraceTime parameter to the SSH server specifies the time allowed for successful authentication to
the SSH server. The longer the Grace period is the more open unauthenticated connections
can exist. Like other session controls in this session the Grace Period should be limited to
appropriate limits to ensure the service is available for needed access. |
|
Set SSH Daemon LogLevel to VERBOSE |
The VERBOSE parameter configures the SSH daemon to record login and logout activity.
To specify the log level in
SSH, add or correct the following line in
/etc/ssh/sshd_config.d/00-complianceascode-hardening.conf:
LogLevel VERBOSE
|
|
Set SSH authentication attempt limit |
The MaxAuthTries parameter specifies the maximum number of authentication attempts
permitted per connection. Once the number of failures reaches half this value, additional failures are logged.
to set MaxAUthTries edit /etc/ssh/sshd_config as follows:
MaxAuthTries
|
|
Set SSH MaxSessions limit |
The MaxSessions parameter specifies the maximum number of open sessions permitted
from a given connection. To set MaxSessions edit
/etc/ssh/sshd_config as follows: MaxSessions
|
|
Ensure SSH MaxStartups is configured |
The MaxStartups parameter specifies the maximum number of concurrent unauthenticated
connections to the SSH daemon. Additional connections will be dropped until authentication
succeeds or the LoginGraceTime expires for a connection. To configure MaxStartups, you should
add or edit the following line in the /etc/ssh/sshd_config file:
MaxStartups
|
|
Remove the X Windows Package Group |
By removing the xorg-x11-server-common package, the system no longer has X Windows
installed. If X Windows is not installed then the system cannot boot into graphical user mode.
This prevents the system from being accidentally or maliciously booted into a graphical.target
mode. To do so, run the following command:
$ sudo dnf groupremove "X Window System"
$ sudo dnf remove xorg-x11-server-common
|
|
Ensure the audit Subsystem is Installed |
The audit package should be installed. |
|
Enable auditd Service |
The auditd service is an essential userspace component of
the Linux Auditing System, as it is responsible for writing audit records to
disk.
The auditd service can be enabled with the following command:
$ sudo systemctl enable auditd.service
|
|
Enable Auditing for Processes Which Start Prior to the Audit Daemon |
To ensure all processes can be audited, even those which start
prior to the audit daemon, add the argument audit=1 to the default
GRUB 2 command line for the Linux operating system.
Configure the default Grub2 kernel command line to contain audit=1 as follows:
# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) audit=1"
|
|
Extend Audit Backlog Limit for the Audit Daemon |
To improve the kernel capacity to queue all log events, even those which occurred
prior to the audit daemon, add the argument audit_backlog_limit=8192 to the default
GRUB 2 command line for the Linux operating system.
Configure the default Grub2 kernel command line to contain audit_backlog_limit=8192 as follows:
# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) audit_backlog_limit=8192"
|
|
Make the auditd Configuration Immutable |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d in order to make the auditd configuration
immutable:
-e 2
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file in order to make the auditd configuration
immutable:
-e 2
With this setting, a reboot will be required to change any audit rules. |
|
Record Events that Modify the System's Mandatory Access Controls |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d:
-w /etc/selinux/ -p wa -k MAC-policy
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/selinux/ -p wa -k MAC-policy
|
|
Record Events that Modify the System's Mandatory Access Controls in usr/share |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d:
-w /usr/share/selinux/ -p wa -k MAC-policy
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /usr/share/selinux/ -p wa -k MAC-policy
|
|
Ensure auditd Collects Information on Exporting to Media (successful) |
At a minimum, the audit system should collect media exportation
events for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
|
|
Record Events that Modify the System's Network Environment |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
|
|
Record Events that Modify the System's Network Environment |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d:
-w /etc/sysconfig/network-scripts -p wa -k audit_rules_networkconfig_modification_network_scripts
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/sysconfig/network-scripts -p wa -k audit_rules_networkconfig_modification_network_scripts
|
|
Record Attempts to Alter Process and Session Initiation Information |
The audit system already collects process information for all
users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
|
|
Record Events When Executables Are Run As Another User |
Verify the system generates an audit record when actions are run as another user.
sudo provides users with temporary elevated privileges to perform operations, either as the superuser or another user.
If audit is using the "auditctl" tool to load the rules, run the following command:
$ sudo grep execve /etc/audit/audit.rules
If audit is using the "augenrules" tool to load the rules, run the following command:
$ sudo grep -r execve /etc/audit/rules.d
-a always,exit -F arch=b32 -S execve -C euid!=uid -F auid!=unset -k user_emulation
-a always,exit -F arch=b64 S execve -C euid!=uid -F auid!=unset -k user_emulation
If both the "b32" and "b64" audit rules for "SUID" files are not defined, this is a finding. |
|
Ensure auditd Collects System Administrator Actions |
At a minimum, the audit system should collect administrator actions
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the default),
add the following line to a file with suffix .rules in the directory
/etc/audit/rules.d:
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions
|
|
Record Events that Modify User/Group Information - /etc/group |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d, in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification
|
|
Record Events that Modify User/Group Information - /etc/gshadow |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d, in order to capture events that modify
account changes:
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
|
|
Record Events that Modify User/Group Information - /etc/security/opasswd |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d, in order to capture events that modify
account changes:
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
|
|
Record Events that Modify User/Group Information - /etc/passwd |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d, in order to capture events that modify
account changes:
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
|
|
Record Events that Modify User/Group Information - /etc/shadow |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d, in order to capture events that modify
account changes:
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
|
|
Record Attempts to perform maintenance activities |
The Amazon Linux 2023 operating system must generate audit records for
privileged activities, nonlocal maintenance, diagnostic sessions and
other system-level access.
Verify the operating system audits activities performed during nonlocal
maintenance and diagnostic sessions. Run the following command:
$ sudo auditctl -l | grep sudo.log
-w /var/log/sudo.log -p wa -k maintenance
|
|
System Audit Logs Must Have Mode 0750 or Less Permissive |
If log_group in /etc/audit/auditd.conf is set to a group other than the root
group account, change the mode of the audit log files with the following command:
$ sudo chmod 0750 /var/log/audit
Otherwise, change the mode of the audit log files with the following command:
$ sudo chmod 0700 /var/log/audit
|
|
System Audit Logs Must Be Group Owned By Root |
All audit logs must be group owned by root user. The path for audit log can
be configured via log_file parameter in /etc/audit/auditd.conf
or, by default, the path for audit log is /var/log/audit/ .
To properly set the group owner of /var/log/audit/*, run the command:
$ sudo chgrp root /var/log/audit/*
If log_group in /etc/audit/auditd.conf is set to a group other
than the root group account, change the group ownership of the audit logs
to this specific group. |
|
Audit Configuration Files Must Be Owned By Group root |
All audit configuration files must be owned by group root.
chown :root /etc/audit/audit*.{rules,conf} /etc/audit/rules.d/*
|
|
Audit Configuration Files Must Be Owned By Root |
All audit configuration files must be owned by root user.
To properly set the owner of /etc/audit/, run the command:
$ sudo chown root /etc/audit/
To properly set the owner of /etc/audit/rules.d/, run the command:
$ sudo chown root /etc/audit/rules.d/
|
|
System Audit Logs Must Be Owned By Root |
All audit logs must be owned by root user. The path for audit log can be
configured via log_file parameter in /etc/audit/auditd.conf
or by default, the path for audit log is /var/log/audit/ .
To properly set the owner of /var/log/audit/*, run the command:
$ sudo chown root /var/log/audit/*
|
|
Audit Configuration Files Permissions are 640 or More Restrictive |
All audit configuration files permissions must be 640 or more restrictive.
chmod 0640 /etc/audit/audit*.{rules,conf} /etc/audit/rules.d/*
|
|
System Audit Logs Must Have Mode 0640 or Less Permissive |
If log_group in /etc/audit/auditd.conf is set to a group other than the
root
group account, change the mode of the audit log files with the following command:
$ sudo chmod 0640 audit_file
Otherwise, change the mode of the audit log files with the following command:
$ sudo chmod 0600 audit_file
|
|
Record Events that Modify the System's Discretionary Access Controls - chmod |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - chown |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - fchmod |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - fchmodat |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - fchown |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - fchownat |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - fremovexattr |
At a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - fsetxattr |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - lchown |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - lremovexattr |
At a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - lsetxattr |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - removexattr |
At a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured to use the augenrules
program to read audit rules during daemon startup (the default), add the
following line to a file with suffix .rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Events that Modify the System's Discretionary Access Controls - setxattr |
At a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
|
|
Record Any Attempts to Run chacl |
At a minimum, the audit system should collect any execution attempt
of the chacl command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
|
|
Record Any Attempts to Run setfacl |
At a minimum, the audit system should collect any execution attempt
of the setfacl command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
|
|
Record Any Attempts to Run chcon |
At a minimum, the audit system should collect any execution attempt
of the chcon command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F path=/usr/bin/chcon -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/chcon -F auid>=1000 -F auid!=unset -F key=privileged
|
|
Ensure auditd Collects File Deletion Events by User - rename |
At a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete
|
|
Ensure auditd Collects File Deletion Events by User - renameat |
At a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete
|
|
Ensure auditd Collects File Deletion Events by User - unlink |
At a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete
|
|
Ensure auditd Collects File Deletion Events by User - unlinkat |
At a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
|
|
Record Unsuccessful Access Attempts to Files - creat |
At a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
|
|
Record Unsuccessful Access Attempts to Files - ftruncate |
At a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
|
|
Record Unsuccessful Access Attempts to Files - open |
At a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
|
|
Record Unsuccessful Access Attempts to Files - openat |
At a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
|
|
Record Unsuccessful Access Attempts to Files - truncate |
At a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
|
|
Ensure auditd Collects Information on Kernel Module Unloading - create_module |
To capture kernel module unloading events, use following line, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S create_module -F key=module-change
Place to add the line depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the line to a file with suffix
.rules in the directory /etc/audit/rules.d.
If the auditd daemon is configured to use the auditctl utility,
add the line to file /etc/audit/audit.rules. |
|
Ensure auditd Collects Information on Kernel Module Unloading - delete_module |
To capture kernel module unloading events, use following line, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S delete_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the line to a file with suffix
.rules in the directory /etc/audit/rules.d.
If the auditd daemon is configured to use the auditctl utility,
add the line to file /etc/audit/audit.rules. |
|
Ensure auditd Collects Information on Kernel Module Loading and Unloading - finit_module |
If the auditd daemon is configured to use the augenrules program
to read audit rules during daemon startup (the default), add the following lines to a file
with suffix .rules in the directory /etc/audit/rules.d to capture kernel module
loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S finit_module -F key=modules
If the auditd daemon is configured to use the auditctl utility to read audit
rules during daemon startup, add the following lines to /etc/audit/audit.rules file
in order to capture kernel module loading and unloading events, setting ARCH to either b32 or
b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S finit_module -F key=modules
|
|
Ensure auditd Collects Information on Kernel Module Loading - init_module |
To capture kernel module loading events, use following line, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S init_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the line to a file with suffix
.rules in the directory /etc/audit/rules.d.
If the auditd daemon is configured to use the auditctl utility,
add the line to file /etc/audit/audit.rules. |
|
Ensure auditd Collects Information on Kernel Module Loading and Unloading - query_module |
If the auditd daemon is configured to use the augenrules program
to read audit rules during daemon startup (the default), add the following lines to a file
with suffix .rules in the directory /etc/audit/rules.d to capture kernel module
loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S query_module -F auid>=1000 -F auid!=unset -F key=modules
If the auditd daemon is configured to use the auditctl utility to read audit
rules during daemon startup, add the following lines to /etc/audit/audit.rules file
in order to capture kernel module loading and unloading events, setting ARCH to either b32 or
b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S query_module -F auid>=1000 -F auid!=unset -F key=modules
|
|
Record Attempts to Alter Logon and Logout Events - faillock |
The audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w -p wa -k logins
|
|
Record Attempts to Alter Logon and Logout Events - lastlog |
The audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins
|
|
Ensure auditd Collects Information on the Use of Privileged Commands |
The audit system should collect information about usage of privileged commands for all users.
These are commands with suid or sgid bits on and they are specially risky in local block
device partitions not mounted with noexec and nosuid options. Therefore, these partitions
should be first identified by the following command:
findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,) | grep -Pv "noexec|nosuid"
For all partitions listed by the previous command, it is necessary to search for
setuid / setgid programs using the following command:
$ sudo find PARTITION -xdev -perm /6000 -type f 2>/dev/null
For each setuid / setgid program identified by the previous command, an audit rule must be
present in the appropriate place using the following line structure:
-a always,exit -F path=PROG_PATH -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the augenrules program to read
audit rules during daemon startup, add the line to a file with suffix .rules in the
/etc/audit/rules.d directory, replacing the PROG_PATH part with the full path
of that setuid / setgid identified program.
If the auditd daemon is configured to use the auditctl utility instead, add
the line to the /etc/audit/audit.rules file, also replacing the PROG_PATH part
with the full path of that setuid / setgid identified program. |
|
Ensure auditd Collects Information on the Use of Privileged Commands - kmod |
At 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:
-w /usr/bin/kmod -p x -k modules
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:
-w /usr/bin/kmod -p x -k modules
|
|
Ensure auditd Collects Information on the Use of Privileged Commands - usermod |
At 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/sbin/usermod -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/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
|
|
Record attempts to alter time through adjtimex |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be
used for better reporting capability through ausearch and aureport. Multiple
system calls can be defined on the same line to save space if desired, but is
not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules
|
|
Record Attempts to Alter Time Through clock_settime |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport.
Multiple system calls can be defined on the same line to save space if
desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules
|
|
Record attempts to alter time through settimeofday |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d:
-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be
used for better reporting capability through ausearch and aureport. Multiple
system calls can be defined on the same line to save space if desired, but is
not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules
|
|
Record Attempts to Alter Time Through stime |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit
lookup table, the corresponding "-F arch=b64" form of this rule is not expected
to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule
form itself is sufficient for both 32 bit and 64 bit systems). If the
auditd daemon is configured to use the auditctl utility to
read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit
lookup table, the corresponding "-F arch=b64" form of this rule is not expected
to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule
form itself is sufficient for both 32 bit and 64 bit systems). The -k option
allows for the specification of a key in string form that can be used for
better reporting capability through ausearch and aureport. Multiple system
calls can be defined on the same line to save space if desired, but is not
required. See an example of multiple combined system calls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules
|
|
Record Attempts to Alter the localtime File |
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the default),
add the following line to a file with suffix .rules in the directory
/etc/audit/rules.d:
-w /etc/localtime -p wa -k audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/localtime -p wa -k audit_time_rules
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport and
should always be used. |
|
Configure auditd mail_acct Action on Low Disk Space |
The auditd service can be configured to send email to
a designated account in certain situations. Add or correct the following line
in /etc/audit/auditd.conf to ensure that administrators are notified
via email for those situations:
action_mail_acct =
|
|
Configure auditd admin_space_left Action on Low Disk Space |
The auditd service can be configured to take an action
when disk space is running low but prior to running out of space completely.
Edit the file /etc/audit/auditd.conf. Add or modify the following line,
substituting ACTION appropriately:
admin_space_left_action = ACTION
Set this value to single to cause the system to switch to single user
mode for corrective action. Acceptable values also include suspend and
halt. For certain systems, the need for availability
outweighs the need to log all actions, and a different setting should be
determined. Details regarding all possible values for ACTION are described in the
auditd.conf man page. |
|
Configure auditd Max Log File Size |
Determine the amount of audit data (in megabytes)
which should be retained in each log file. Edit the file
/etc/audit/auditd.conf. Add or modify the following line, substituting
the correct value of for STOREMB:
max_log_file = STOREMB
Set the value to 6 (MB) or higher for general-purpose systems.
Larger values, of course,
support retention of even more audit data. |
|
Configure auditd max_log_file_action Upon Reaching Maximum Log Size |
The default action to take when the logs reach their maximum size
is to rotate the log files, discarding the oldest one. To configure the action taken
by auditd, add or correct the line in /etc/audit/auditd.conf:
max_log_file_action = ACTION
Possible values for ACTION are described in the auditd.conf man
page. These include:
ignoresyslogsuspendrotatekeep_logs
Set the ACTION to |
|
Configure auditd space_left Action on Low Disk Space |
The auditd service can be configured to take an action
when disk space starts to run low.
Edit the file /etc/audit/auditd.conf. Modify the following line,
substituting ACTION appropriately:
space_left_action = ACTION
Possible values for ACTION are described in the auditd.conf man page.
These include:
syslogemailexecsuspendsinglehalt
Set this to email (instead of the default,
which is suspend) as it is more likely to get prompt attention. Acceptable values
also include suspend, single, and halt. |