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W32.Bugbear@mm, also known as Tanatos, is a sophisticated mass-mailing worm. Bugbear exploits the Incorrect MIME header vulnerability in Microsoft Internet Explorer to infect e-mail users, but can also spread itself via open network resources. The infected e-mail messages arrive with varying subject lines, text bodies, and file attachments making manual recognition of the virus nearly impossible.

In addition, the Bugbear worm carries a Trojan horse, which can disable antivirus and firewall software, thus compromising the computer's security settings, and log keystrokes enabling hackers to uncover personal information such as passwords, credit card numbers, and more.

All users of Internet Explorer 5.01 and 5.5 should update their browsers now! Svetlozar Online recommends that you download and install the latest virus definitions available from your antivirus software maker.