A worm that spreads through Microsoft Corp.'s MSN Messenger instant messaging program is circulating on the Internet. If released on a computer, the worm opens a back door to the infected machine and e-mails product keys for popular PC games such as Half-Life to an anonymous Web-based e-mail account, according to an alert posted on the Web page of antivirus maker Sophos PLC.
The new worm, dubbed "W32/Rodok-A" or "Henpeck" uses MSN Messenger to circulate a message enticing users into downloading and running an executable file named "BR2002.exe" from a remote Web site, according to Sophos.
The message reads, in part:
"Hey!! Could you please check out this program for me? :) I made it myself and want people to test it. Its a readme with the program that explains what it does!"
A link is provided in the instant message to the location of the worm on the Internet. When users download and launch the program, the worm displays a phony CD key generating program. Behind the scenes, it connects back to the same Web page from which it was downloaded, retrieves an updated version of itself, and attempts to download and place a so-called "trojan" on the infected machine. The Web site containing the worm was offline early Friday, however.
Trojans are programs that allow the machine on which they reside to be used as part of a distributed denial of service (DDoS) attack orchestrated by a remote attacker.
The particular trojan installed by the MSN worm is known as "BKDR_EVILBOT" and can be accessed and manipulated with commands transmitted using Internet Relay Chat (IRC), according to an alert posted on the Web page of antivirus company Trend Micro Inc.
In addition to opening a back door to the machine and installing updated versions of itself, the worm appears to search for and copy any product keys for games that are installed on the infected machine. Among the games it searches for, according to Sophos, is Half-Life by Sierra Entertainment Inc. Any product keys the worm discovers are e-mailed to an anonymous Hotmail account from which the virus author can retrieve them.
For users who have been infected, removing the worm entails shutting down the trojan software and editing the Windows registry to remove settings that launch the worm automatically when Windows starts.
The threat posed by the new MSN worm was rated as "low" by most antivirus makers. Despite that fact, and the fact that there were few reports of users being infected by the new worm, many antivirus software makers posted updates to their software Wednesday and Thursday covering Rodok-A/Henpeck.