This is expected behaviour. The libpam-script _already_ adds the pam_script.so module to the system on installation.
For example, from the common-auth file: common-auth:auth sufficient pam_script.so Since you are exiting with 0, this is sufficient to grant access. ** Changed in: libpam-script (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1325240 Title: Lockscreen bypass with empty or wrong password To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libpam-script/+bug/1325240/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs