Apple Security Update
Apple just released a security update today that isolates several key files that the MacDefender malware uses. Be sure to update by using your software update function or by going to Apple’s website here: http://support.apple.com/kb/DL1387. But it also has it’s own updating list, so that the built in Mac malware protection can update on it’s own without having to got through software update. You can opt out of this by going to the Security Preference Pan, and unchecking “Automatic Updating”.