Vulnerability Discussion
By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking the account.
Satisfies: SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005
Check
Verify RHEL 9 is configured to lock the root account after three unsuccessful logon attempts with the command:
$ sudo grep even_deny_root /etc/security/faillock.conf
even_deny_root
If the "even_deny_root" option is not set or is missing or commented out, this is a finding.
Fix
To configure RHEL 9 to lock out the "root" account after a number of incorrect logon attempts using "pam_faillock.so", first enable the feature using the following command:
$ sudo authselect enable-feature with-faillock
Edit the "/etc/security/faillock.conf" by uncommenting or adding the following line:
even_deny_root