Experts: 'Mydoom' virus is vicious
An e-mail worm that looks like a normal error message but actually contains a malicious program snarled computers around the world on Tuesday.
MessageLabs Inc., which scans e-mail for viruses, said one in every 12 messages contained the worm, called "Mydoom" or "Novarg." Security experts described it as the largest virus-like outbreak in months.
The worm began spreading rapidly Monday during business hours in the United States. By comparison, many previous outbreaks had started during Asian business hours, allowing antivirus vendors to develop defenses by the time U.S. companies opened up shop.
"Whenever a virus begins to start in the States, it usually becomes much bigger," said Vincent Gullotto, an antivirus researcher at Network Associates Inc.
Some corporate networks were clogged with infected traffic within hours of the worm's appearance, and operators of many systems voluntarily shut down their e-mail systems.
Mikko Hypponen, manager of anti-virus research at F-Secure Corp. in Finland, estimated that 200,000 to 300,000 computers were hit worldwide.
The worm infects computers using Microsoft Corp.'s Windows operating systems, though other computers were affected by network slowdowns and a flood of bogus messages.
