Microsoft will pay a US$250,000 reward for information leading to the arrest and conviction of the person or persons responsible for releasing the Mydoom-B worm, the company has said.
The offer is part of Microsoft's $5 million bounty programme to reward people for information relating to worm and virus authors, announced last November.
The Mydoom-B worm is similar to the Mydoom-A worm that appeared on Monday, but additionally contains a scheduled denial of service (DOS) attack against Microsoft's Web site and a feature that blocks access to anti-virus Web sites on infected machines.
Residents of any country are eligible for the award, Microsoft said.
According to Microsoft, the attack against the www.microsoft.com website is scheduled for February, which begins on Saturday.
Microsoft said it is working with the Federal Bureau of Investigation (FBI), the U. S. Secret Service and Interpol in investigating the Mydoom-B worm, the release of which Microsoft described as a "criminal attack".