Microsoft and FBI Wednesday announced that in a joint operation, they took down over 1,000 Citadel botnets that were being used to control millions of malware-infected PCs.

　Over the past 18 months, authorities believe the botnets stole over $500 million from consumer and business bank accounts, infecting more than 5 million PCs located in 90 countries, including the United States, Australia, Hong Kong, India and large parts of Western Europe.

　The takedown began last week, when Microsoft filed a civil lawsuit against the botnet "herders" running 1,463 Citadel botnets. Using a court-ordered seizure request and working with U.S. Marshalls, Microsoft employees seized servers from two hosting facilities in New Jersey and Philadelphia and provided information about the botnets to overseas Computer Emergency Response Teams (CERTs), requesting that they target related command-and-control infrastructure. The FBI simultaneously provided related information to its overseas law enforcement counterparts.