New attack bypasses virtually all AV protection

New attack bypasses virtually all AV protection Bait, switch, exploit!

By Dan Goodin in San Francisco

Posted in Security, 7th May 2010 18:17 GMT

Researchers say they've devised a way to bypass protections built in to dozens of the most popular desktop anti-virus products, including those offered by McAfee, Trend Micro, AVG, and BitDefender.

The method, developed by software security researchers at matousec.com

works by exploiting the driver hooks the anti-virus programs bury deep inside the Windows operating system. In essence, it works by sending them a sample of benign code that passes their security checks and then, before it's executed, swaps it out with a malicious payload.

The exploit has to be timed just right so the benign code isn't switched too soon or too late. But for systems running on multicore processors, matousec's "argument-switch" attack is fairly reliable because one thread is often unable to keep track of other simultaneously running threads. As a result, the vast majority of malware protection offered for Windows PCs can be tricked into allowing malicious code that under normal conditions would be blocked.

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