Vulnerability Discussion

Limiting the number of logon attempts over a certain time interval reduces the chances that an unauthorized user may gain access to an account.

The delay option is set in microseconds.

Check

Verify Ubuntu 24.04 LTS enforces a delay of at least four seconds between logon prompts following a failed logon attempt with the following command:

$ grep pam_faildelay /etc/pam.d/common-auth
auth required pam_faildelay.so delay=4000000

If the value for "delay" is not set to "4000000" or greater, the line is commented out, or is missing, this is a finding.

Fix

Configure Ubuntu 24.04 LTS to enforce a delay of at least four seconds between logon prompts following a failed logon attempt.

Edit the file "/etc/pam.d/common-auth" and set the parameter "pam_faildelay" to a value of "4000000" or greater:

auth required pam_faildelay.so delay=4000000