Gokar worm spreads by e-mail, Web, chat

IDG News Service - A new worm called Gokar began to spread across the Internet today via e-mail, the chat program mIRC and the Web, according to a trio of antivirus firms.

The worm isn't destructive and hasn't yet infected many systems, but as with any mass-mailer worm, it could become a nuisance as unsuspecting users spread it. Like other mass-mailing worms such as Anna Kournikova or Badtrans, Gokar spreads through Microsoft Corp.'s Outlook and Outlook Express e-mail clients when a user clicks on an attachment sent with the infected message, according to antivirus firms Symantec Corp., F-Secure Corp. and Trend Micro Inc.

Infected e-mail arrives in user in-boxes with dozens of combinations of different subject lines, body messages and file names, though attachments will end with a .pif, .scr, .exe, .com or .bat extension, the companies said.

When the attachment is double-clicked, the worm installs a file called Karen.exe on the infected system and mails itself to all addresses listed in the computer's address book. The worm then runs every time the infected computer is booted up. Users can determine whether a system is infected or not by searching for the Karen.exe file.

The worm also uses the Internet Relay Chat program mIRC, the companies said. Gokar searches the infected PC for the mIRC application. If it finds it, it attempts to infect IRC users in the same discussion, or channel, as the infected system whenever the application is started, according to Tokyo-based Trend Micro.

Finally, if an infected system is running Microsoft's Internet Information Server (IIS) Web server software, the worm will modify the default Web page on the system and offer users visiting the site a chance to download the worm, according to Helsinki, Finland-based F-Secure. An infected Web site will be changed to display the text "We are Forever" and point users to a link to download a file called Web.exe, which contains the Gokar worm, according to Cupertino, Calif.-based Symantec.

The Nimda worm also defaced Web sites and downloaded files to the computers of users viewing the defaced sites. Unlike Nimda, which automatically downloaded a file through the browser, Gokar requires that the user click a link to download the worm.

Nimda and the Code Red worm both also exploited IIS.

Users should check with their antivirus companies for software updates. Companies are urged to block attachments, especially .exe, .scr or .pif files, at their mail gateways to avoid infection.



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