Vulnerability Discussion
Having lockouts persist across reboots ensures that account is only unlocked by an administrator. If the lockouts did not persist across reboots, an attacker could simply reboot the system to continue brute force attacks against the accounts on the system.
Check
Verify the "/etc/security/faillock.conf" file is configured use a nondefault faillock directory to ensure contents persist after reboot with the following command:
$ grep 'dir =' /etc/security/faillock.conf
dir = /var/log/faillock
If the "dir" option is not set to a nondefault documented tally log directory, is missing or commented out, this is a finding.
Fix
Configure RHEL 9 maintain the contents of the faillock directory after a reboot.
Add/modify the "/etc/security/faillock.conf" file to match the following line:
dir = /var/log/faillock