We found a tool at http://www.windowsecurity.com/emailsecuritytest/ that will allow you to test various aspects of your mail setup, including how your mail reading program responds to various kinds of security attacks.  You or your system administrator may wish to run this test once in a while to verify that your security systems are working.

If you're looking for a modern e-mail reading program that has great security measures built in, you might try Thunderbird.