This sounds much like bug 32906. Can you please check whether 'localhost' is in /etc/hosts?
** Changed in: sudo (Ubuntu)
Status: New => Incomplete
--
sudo hangs before prompting for password in hardy alpha 4
https://bugs.launchpad.net/bugs/193963
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
