BadBehavior is a module for the Zikula Application Framework that implements the Bad Behavior php library from http://bad-behavior.ioerror.us/ from Michael Hampton.
"Bad Behavior is one of the Internet’s most trusted solutions for helping to prevent link spam and other malicious activity, from well-known sites to the smallest blogs.
"Bad Behavior complements other link spam solutions by acting as a gatekeeper, preventing spammers from ever delivering their junk, and in many cases, from ever reading your site in the first place. This keeps your site’s load down, makes your site logs cleaner, and can help prevent denial of service conditions caused by spammers."
You can donate to the continued development of the vendor library at http://bad-behavior.ioerror.us/donate/