Virus alert: AIM worm on the loose

A new AOL instant-messaging worm is making the rounds, carrying a malicious payload disguised as a JPEG, according to security researchers.

The worm provides a path for rootkits and Trojan horses to propagate on the computers of those listed on the user's buddy list, according to an advisory issued on Monday by FaceTime Security Labs. The W32.pipeline worm is one of a growing number of instant-messaging threats on the internet.

W32.pipeline initially appears as an instant message from a familiar contact, according to FaceTime security. A message appears asking users to click on a link to upload a picture of themselves; instead, a command file, image18.com, is downloaded and disguised as a JPEG, according to FaceTime.

Once the user runs the file, a csts.exe is created and installed in the user's system32 folder, as part of the Windows operating system. After a user's system is infected, it becomes part of a botnet - a group of computers controlled remotely to distribute such malicious attacks as viruses or Trojans.

Chris Boyd, FaceTime's malware research director, said in a statement: "The emphasis for this latest worm is not so much on the files that are delivered to the users' computers but rather on the way these files are deposited onto the system."

Dawn Kawamoto writes for CNET News.com