Slow SSH and sudo Login (Ubuntu)

I have been annoyed by extremely slow SSH logins to an Ubuntu VM of mine for a while now. Both the login and password prompt displayed quickly enough and there was no delay in keyboard input, however after submitting my password I'd be faced with a delay of somewhere between 10 and 30 seconds. I had begun noticing similar delays when using sudo to switch to root (though these delays weren't quite as long).

My threshold of annoyance was finally crossed this evening and I decided I'd better figure out why this was occurring. Most resources I found online seemed to point in the direction of ensuring "UseDNS no" has been set in /etc/ssh/sshd_config, unfortunately this was not the problem in my case.

After digging around a bit longer, I bumped into a helpful thread on the Ubuntu forums that pointed out the actual problem was likely with PAM.

Making the recommended change by commenting out the following PAM connector in /etc/pam.d/common-session did the trick.

# session       optional                        pam_ck_connector.so nox11