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.

Check

Verify AlmaLinux OS 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 is commented out, this is a finding.

Fix

Configure AlmaLinux OS 9 to lock accounts until released by an administrator using pam_faillock.

First, enable the feature using the following command:

$ authselect enable-feature with-faillock

Then, add or uncomment the following line in the "/etc/security/faillock.conf" file:

unlock_time = 0