W32.Swen.A

W32.Swen.A@mm is a worm that uses its own SMTP engine to spread itself. It attempts to spread through file-sharing networks, such as KaZaA and IRC, and also attempts to kill antivirus and personal firewall applications running on a PC.

The worm can arrive as an email attachment. The appearance of the email may vary.

This worm exploits a vulnerability in Microsoft Outlook and Outlook Express in an attempt to execute itself when you open or even preview the message. Information and a patch for the vulnerability can be found at
http://www.microsoft.com/technet/security/bulletin/MS01-020.asp