Tool IDs Hidden Malware

ARLINGTON, Va. -- Black Hat DC -- A security software vendor is close to rolling out a new tool that will help IT staffers identify malware -- even when the attacker has taken pains to hide it in packed files.

In a presentation here at the Black Hat conference yesterday, officials from Mandiant -- a professional services firm and incident response software maker -- demonstrated an as-yet-unannounced tool that can identify malware even after it has been "packed" to avoid detection.

Packing -- the compression of data files to speed transmission over a network -- is becoming an increasingly popular method for slipping malware past antivirus applications and other tools that detect suspicious files, noted Mandiant's Chad McMillan, who demonstrated the new tool.

By placing malware among multiple "zipped" files in a transmission, packing enables malware authors to hide their attachments in a larger envelope that carries a new filename -- one not recognized by the antivirus software. "It can be a pretty effective way to armor malware," McMillan said.

To counter packed malware, Mandiant has developed Caprica Six, a software program that can read the headers of packed (PE) files and scan for anomalies that might indicate the presence of malware. "It looks for things like incorrect image size, unaligned sections, non-ASCII section names, and overlapping headers, then flags them," McMillan said.

Caprica Six also can search packed sections for malware signatures, helping security staffers to identify "fake code" that may be used to camouflage malicious programs, McMillan stated.

The new product won't identify malware with perfect accuracy, but it will kick out suspicious files and code so that a human can investigate them further, McMillan said. "Instead of looking through thousands of files, you might have eight or nine."

The Mandiant presenters did not say when the new software will be available or how much it will cost. "We expect to have it ready soon," McMillan said.

— Tim Wilson, Site Editor, Dark Reading