The Conficker Virus has infected an estimated 12 million systems worldwide and continually updates itself by contacting a seemingly random string of fake domain names.
According to a statement by MS the Conficker is being viewed as a criminal attack, as such a monetary reward is being offered to help apprehend the people responsible.
For $250,000 someone might leak something.
Read more here at CNet.
Microsoft said it is offering the reward because the worm constitutes a "criminal attack" and offering compensation should hasten prosecution. Residents of any country are eligible for the reward and should contact their international law enforcement authorities, the company said in a statement.
Microsoft also announced that it has partnered with security companies, domain name providers, and others on a coordinated global response to the worm, also known as Downadup. Participating are: the Internet Corporation for Assigned Names and Numbers (ICANN), VeriSign, NeuStar, CNNIC, Afilias, Public Internet Registry, Global Domains International, M1D Global, AOL, Symantec, F-Secure, ISC, Georgia Tech, the Shadowserver Foundation, Arbor Networks, and Support Intelligence.
The worm, which has been around since last year, spreads through a hole in Windows systems, exploiting a vulnerability that Microsoft patched in October.