Vulnerability Discussion

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account.

From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable, a different tally directory must be set with the "dir" option.

SELinux, enforcing a targeted policy, will require any non-default tally directory's security context type to match the default directory's security context type. Without updating the security context type, the pam_faillock module will not write failed login attempts to the non-default tally directory.

Check

If the system does not have SELinux enabled and enforcing a targeted policy, or if the pam_faillock module is not configured for use, this requirement is not applicable.

Note: This check applies to RHEL versions 8.0 and 8.1. If the system is RHEL version 8.2 or newer, this check is not applicable.

Verify the location of the non-default tally directory for the pam_faillock module with the following command:

$ sudo grep -w dir /etc/pam.d/password-auth

auth required pam_faillock.so preauth dir=/var/log/faillock
auth required pam_faillock.so authfail dir=/var/log/faillock

Check the security context type of the non-default tally directory with the following command:

$ sudo ls -Zd /var/log/faillock

unconfined_u:object_r:faillog_t:s0 /var/log/faillock

If the security context type of the non-default tally directory is not "faillog_t", this is a finding.

Fix

Configure RHEL 8 to allow the use of a non-default faillock tally directory while SELinux enforces a targeted policy.

Update the /etc/selinux/targeted/contexts/files/file_contexts.local with "faillog_t" context type for the non-default faillock tally directory with the following command:

$ sudo semanage fcontext -a -t faillog_t "/var/log/faillock(/.*)?"

Next, update the context type of the non-default faillock directory/subdirectories and files with the following command:

$ sudo restorecon -R -v /var/log/faillock