TOSS 5 must not allow blank or null passwords.

If an account has an empty password, anyone could log in and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.

Verify null passwords cannot be used by running the following command:

$ sudo grep -i nullok /etc/pam.d/system-auth /etc/pam.d/password-auth

If an output is produced, this is a finding.

Remove any instances of the "nullok" option in the "/etc/pam.d/password-auth" and "/etc/pam.d/system-auth" files to prevent logons with empty passwords.

Note: Manual changes to the listed file may be overwritten by the "authselect" program.