Microsoft announced it will offer a $250,000 bounty for the one who helps them track down and prosecute the creator of the Conficker (Downadup) worm. This strategy already worked four times. The last time Microsoft offered a bounty, in 2005, it led to the capture and conviction of the Sasser worm author.

This bounty represents the culmination of an unprecedented collaborative response from industry, academia and Internet policy groups in order to fight the Conficker worm’s spreading and to also find out who is responsible for this “criminal act,” as Microsoft described it in a statement.

Botnets have gotten more and more sophisticated and the Conficker makes no exception. The problem has become too big for any single group or organization to handle, said Vincent Weafer, vice president of Symantec Security Response.

It is not sure yet how many systems were infected by the Conficker worm. Some estimates said about 2 million PC were infected, while other industry experts believe the number could be as high as 10 million. Microsoft just said at least 3 million PC were affected.

Residents from any country can get their hands on the $250,000 bounty by providing any information leading to the arrest and conviction of malware authors who unleashed Conficker.

There are some security experts who believe Conficker is just the first state of a larger attack.

"This worm would be a marvelous tool in hands of whoever can control it, but the real harm from it has yet to be felt, and we're trying to postpone that day," said Paul Vixie, founder of Internet Systems Consortium, a Redwood City, Calif.