Why would you trust the toolchain on a potentially hacked machine?
There's an old paper by Ken Thompson that dicusses patching the C
compiler to recognize the login sources and re-introduce a backdoor -
even it was removed from the login sources.
You would be much better off booting a fixit CD-ROM and using that
rather than trusting anything on the potentially hacked system.
Indeed, one should make a backup copy (if possible) of the potentially
hacked computer (Drive) and take the machine offline.
Then insert the backupdisk in a other pc, (or the same, with the
original hd stored safely) and startup your Live-cd kit (which can be a
freebsd version from cd, or linux). Make sure that the tools necessary
are on the live cd;-) and to forensics (tct might help (The Coroners
After finding out what happened, format the disk, and reinstall from
scratch, be hostile to every config file and stuff you backupped,
because you might not be able to tell when the potential hack took