With the aim to find who is behind the Downadup/Conficker virus, Microsoft has announced a reward of $250,000 (£172,000) to who so ever will come up with the answer.

The Conficker worm that started circulating in October 2008 has been successful in infecting millions of computers worldwide.

The reward is being offered by the software giant, since it sees the Conficker worm as a criminal attack.

George Stathakopulos from Microsoft's Trustworthy Computing Group reported, "People who write this malware have to be held accountable."

He further informed, "The Company is not prepared to sit back and let this kind of activity go unchecked."

Mr Stathakopulos further said, "Our message is very clear - whoever wrote this caused significant pain to our customers and we are sending a message that we will do everything we can to help with your arrest."

Since Conficker/Downadup commenced prowling the web looking for vulnerable machines to infect in October, it can infect as many as 12 million computers globally.

Basically, the Conficker worm is a self-replicating program and it takes advantage of networks or computers which have not kept up to date with Windows security patches.

The machines can also be infected by it through a net connection and the worm can also hide itself on USB memory drives used to ferry data from one computer to another. One the worm reaches the computer, it goes deep, making defenses for itself, thus making it hard to extract.

It has also been learnt that Microsoft has also partnered with security companies, domain name providers, academia, internet companies such as AOL and others on a co-ordinated global response to the worm.