Enforcement of Delay Between Logon Prompts Following a Failed Logon Attempt.

The Ubuntu operating system must enforce a delay of at least 4 seconds between logon prompts following a failed logon attempt.

Rationale:

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

Audit:

Verify the Ubuntu operating system enforces a delay of at least 4 seconds between logon prompts following a failed logon attempt.

Check that the Ubuntu operating system enforces a delay of at least 4 seconds between logon prompts with the following command:

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

If the line is not present, or is commented out, this is a finding.

Remediation:

Configure the Ubuntu operating system to enforce a delay of at least 4 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