I don't understand how you can be so confidently wrong about something so easily checked. :D
> You can't run unix_chkpwd against a local account without root because you won't be able to access /etc/shadow to get the hash.
unix_chkpwd can access /etc/shadow because it is suid.
> Otherwise you have to use the setuid version which won't let you run it directly.
Haha you mean this?
$ unix_chkpwd
This binary is not designed for running in this way
-- the system administrator has been informed
Take a look at the source code I linked about 6 comments ago!
> Perhaps try checking something yourself?
I have. You haven't.
printf 'hunter2\0' | unix_chkpwd yourusername nullok; echo $?