The newest threat, said Ken Dunham, director of VeriSign iDefense's rapid response team, hides within an apparently innocent PowerPoint slide show, "Christmas+Blessing-4.ppt," which is attached to an e-mail message. The PowerPoint file, which circulated sans exploits last year around Christmas, has been making the rounds since Sunday.
"The reality is that this is a very popular file," said Dunham, "and poorly detected by most antivirus scanners." However, some security companies, including F-Secure, have created signatures to sniff out the threat.
More important is that Christmas+Blessing-4 shares characteristics with the Office document-based attacks that began seven months ago. "This is very similar to other Office attacks from May and June," Dunham said. "It's a targeted attack, this time [against a company] in the public utility sector."
Other Office document exploits--which included ones leveraging zero-day vulnerabilities in Word, Excel, and PowerPoint--also were limited in scope. But that doesn't make them less dangerous, said Dunham. "This kind of attack will be one of the most concerning during 2007. It will be the one that keeps CEOs up at night."
Unlike those earlier attacks, Christmas+Blessing-4 is not a zero-day exploit taking advantage of a vulnerability that hasn't been fixed. "It doesn't work on fully patched computers," Dunham said. After a user opens the PowerPoint file, a variant of the "Hupigon" backdoor Trojan horse is installed on the PC. The Trojan then silently adds two additional files, "msupdate.dll" and "sdfsc.dll," to the system.
IDefense said that the crew responsible for the newest Office attack was Chinese, another similarity with the summer's Word and Excel exploits. Calling the writers "hackers for hire," Dunham said that the rapid shift in China from politically motivated attacks to for-profit hacks is "a cause for concern."
"They're getting paid a whole lot of money," Dunham said. "The capitalist attitude is infiltrating Chinese hackers."
Dunham recommends that users patch their systems--Microsoft Office applications as well as Windows--and refuse to open unsolicited PowerPoint files, especially any attached to e-mails with the subject of "Merry Christmas to our hero sons and daughters!"
Warned Dunham, "If you're not patching promptly, you can expect attacks in 2007."