Microsoft is considering whether to offer a bounty for information that leads to the arrest of the Mydoom virus author, according to company spokesperson.
Microsoft was working with antivirus companies and the US Federal Bureau of Investigation (FBI) about whether to put out a bounty, but hadn't yet reached a decision, he said.
Mydoom is a computer virus that first appeared on Monday. A version targets computers running Microsoft's Windows operating system. The worm spreads through infected email file attachments and the Kazaa peer-to-peer network.
Mydoom quickly spread worldwide, infecting between 400,000 and 500,000 computers as of Thursday, according to Network Associates.
Microsoft first unveiled its bounty program last November, calling viruses and worms "criminal acts" and pledging $US5 million for bounties to catch the authors of virulent worms and viruses. So far, Microsoft offered bounties of $US250,000 for information leading to the arrest and conviction of the individuals who created the Blaster and Sobig worms, which appeared last August.
However, it has not attached a bounty to any other worm or virus outbreak since then, leaving much of the $US5 million untouched. On Tuesday, corporate vice-president of Microsoft's Security Business Unit, Mike Nash, said that a bounty was "possible" in the case of the Mydoom author.
Microsoft considers a number of factors before it decided to offer a bounty, including the number of systems infected by the worm and the amount of damage caused, Nash said.
The company also looked at the severity rating assigned to worms and viruses by antivirus companies such as Symantec and Network Associates' McAfee antivirus unit, the spokesperson said.
"We're considering it right now and we're working with law enforcement to help make a decision about whether to offer a bounty," he said.