PowerPoint Trojan: Not Zero Day

Sigh of relief: Researchers concluded this morning that the new PowerPoint Trojan is not a zero day exploit after all.

The so-called Troj_Mdropper.BH (See Trojan May Threaten PowerPoint.) actually exploits a known and patched vulnerability in Office, MS06-012, according to an update on Trend Micro's malware blog today.

The Trojan confounded researchers around the industry yesterday because it didn't display the same behaviors of other malware that goes after the remote-code execution vulnerabilities in Office that were patched in MS06-012. Researchers initially thought it could be targeting a new, unknown vulnerability in Microsoft software and spent most of yesterday and last night testing it out.

"When we put up a statement like it uses 'an unknown vulnerability,' we are in the middle of our investigation and don't know if it is or not yet," says David Perry, global director of education for Trend Micro.

The Trojan's shell code doesn't "manifest" the same behavior as other exploits that target the vulnerability, Trend Micro said in its update.

— Kelly Jackson Higgins, Senior Editor, Dark Reading