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.

Check

Verify Amazon Linux 2023 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 Amazon Linux 2023 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