Comment 11 for bug 562146

> I was sure that libpam to acces shadow uses some suid helper program.
> So i was wrong about it...

There is a suid helper program in pam_unix, called unix_chkpwd. But for obvious reasons it only allows to check the password of the current user, which is in turn used by programs like gnome-screensaver to verify the password. It does not work for brute-forcing or checking any other user's password.