Anti-malware products are not 100% effective, as evidenced by our recent anti-malware tests. In fact, some seem to be falling behind the bad guys.
Why? Because the bad guys are smart and aggressive. And remember, cybercriminals need only find one open door to get in, whereas defenders need to protect all the doors.
Cybercriminals are employing a plethora of techniques in a highly automated fashion to evade detection. Gunter Ollman and the Damballa team have written a nice paper explaining malware evasion techniques. These automated methods allow bad guys to create massive amounts of unique malware that can circumvent AV software. Popular techniques include using:
5. Quality Assurance
See the well-written paper for a more complete discussion. This is why AV products are having to evolve, and quickly.