Vulnerability Discussion
By limiting the number of failed logon attempts the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account.
Satisfies: SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005
Check
Verify RHEL 9 is configured to lock an account until released by an administrator after three unsuccessful logon attempts with the command:
$ grep 'unlock_time =' /etc/security/faillock.conf
unlock_time = 0
If the "unlock_time" option is not set to "0", the line is missing, or commented out, this is a finding.
Fix
Configure RHEL 9 to lock an account until released by an administrator after three unsuccessful logon attempts with the command:
$ authselect enable-feature with-faillock
Then edit the "/etc/security/faillock.conf" file as follows:
unlock_time = 0