Hello Scott!
One symptom I'm working on is QmailAdmin. After I successfully log into the cgi, I get a defaced page. I looked at the cgi and looked to me like it posts to itself. If that's the case - and it hasn't been messed with, then how am I getting the cracker's page? Does QmailAdmin use templates?
Qmailadmin is just one binary and some png images. Check your qmailadmin source tree for changes. e.g. make a diff against a clean source tree. And please tell us which version you are using. Claas