The Security Mentor

According to a Cambridge University security researcher I talked to, and according to CNet, it's possible for an unpatched Microsoft system to get taken over by a tainted picture before the antivirus software has had a chance to check it.

Windows Update is the best line of defense, and it's important to update now that bad guys are trying this attack in real life. The latest I heard of was on instant messaging, where a message saying "check out my profile!" went to a picture with a virus payload. That particular attack reportedly failed but it's only going to get worse.