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 the root account after three unsuccessful logon attempts with the command:

$ grep even_deny_root /etc/security/faillock.conf
even_deny_root

If the "even_deny_root" option is not set, is missing or commented out, this is a finding.

Fix

Configure Amazon Linux 2023 to lock out the "root" account after a number of incorrect login attempts using "pam_faillock.so", first enable the feature using the following command:

$ sudo authselect enable-feature with-faillock

Then edit the "/etc/security/faillock.conf" file as follows:

add or uncomment the following line:
even_deny_root