New IM Worms Delete Files, Hijack PCs

An anti-virus vendor warned Tuesday that two new worms spreading on Microsoft's and America Online's instant messaging networks delete files and leave systems open to hijacking.

Symantec posted alerts for the "Hotmatom" and "Maniccum" worms, and ranked both as a level "2" threat. The Cupertino, Calif.-based security company uses a 1 through 5 scale to label worms, viruses, and Trojans.

Hotmatom, said Symantec, is a Spanish-language worm transmitted over Microsoft's MSN instant messaging network. A message arrives, seemingly from a trusted IM contact, that claims a "very dangerous virus" (virus muy peligroso) has been detected, and offers a link to a free patch. Clicking on the link, however, actually installs the worm.

Once on a PC, Hotmatom deletes files at the root level of the A:/ and C:/ drives, then assigns those deleted filenames to copies of itself.

It also appends text to any future Microsoft Hotmail e-mail messages sent by that computer; the text, which can be in either Spanish or English, includes links to the same malicious code.Maniccum, meanwhile, propagates via both America Online's AIM and MSN's networks, and if installed, opens a backdoor on that PC and tries to disable security programs, including anti-virus and firewall software.

The backdoor, which accepts commands from the attacker via IRC, can be used to access files, update the worm, upload more malicious code, send additional AIM and/or MSN messages, and launch denial-of-service (DoS) attacks, said Symantec.