MyDoomB spreading, worse than first

A new version of the "Mydoom" e-mail worm that appeared on the Internet Wednesday makes it more difficult for computer users to download updated security software and instructs infected computers to attack Microsoft Corp.'s Internet homepage, security experts said.

The worm prevents victims from getting on Microsoft's Windows Update page, which hosts the company's latest software fixes and patches, as well as more than 60 other sites that contain anti-virus software. It also blocks Web site advertisements that are provided by Internet ad firm DoubleClick Inc.

Mydoom.B replaces the older version of itself on infected computers, said Tony Magallanez, a systems engineer with F-Secure Corp., an anti-virus company in San Jose, Calif. The first version punches a hole in the victim's Internet connection that allows attackers to take control of the computer or install malicious software.

Magallanez said that Mydoom.B does not require users with computers infected by the first version to click on a new attachment to activate it. Instead, Mydoom.B scans the Internet for infected computers and updates itself.

A one-two sucker punch. This will be bad.