Microsoft Claims It Took Down Rustock

SEATTLE — Microsoft is claiming it has taken down the massive Rustock botnet, which is one of the biggest producers of spam email.

The software giant's legal action against the operator of the botnet led to raids across the U.S. on Thursday, which effectively shut the network down.

Microsoft worked with the U.S. Marshals Service to raid hosting providers in seven U.S. cities, including Denver, Dallas, Chicago, Kansas City, Seattle, Scranton, Pa., and Columbus, after getting a green light from a judge at U.S. District Court in Seattle.

The suit — Microsoft Corp. vs. John Does 1-11 Controlling a Computer Botnet Thereby Injuring Microsoft and Its Customers — describes the unnamed defendants as John Does who control "an illegal, notorious and worldwide network" of 1 million computers infected with Rustock malware, sending out as many as 30 billion spam emails per day, without their users' knowledge.

Microsoft bases its complaint on a variety of legal grounds, including trademark infringement and violation of the Can-Spam Act. The suit also includes a series of maps that depict locations of botnet servers and of infected computers.

Microsoft's legal tactics went in tandem with other operation against Rustock. Command and control servers were taken down through work with the ISPs and some international authorities.