it's quite likely imap or even the default exchange protocol, but either way the authentication is probably as part of the logon to a workstation...and without exchange admin help regards exact alternative authentication using a script, you'll be struggling to get anywhere...and maybe you'll end up getting noticed by locking someone's email/logon account. it's illegal in most countries to eavesdrop without good reason and proper authority. the simplest way is for the exchange admin to setup a invisible automated cc or forward to another address.
in reply to Connect to Microsoft Exchange
the hardest line to type correctly is: stty erase ^H