After winning a summary judgment against the perpetrators of the massive spamming network, the software giant hands evidence to federal law enforcement, including clues about the alleged ringleader.
Taken down in March, the Rustock botnet is still "dead and decaying," says Microsoft, but the company still hopes to track down the culprits in Russia using a series of ads and legal filings.
A raid, triggered by a Microsoft lawsuit, neutralized the massive spamming network last week.
The Rustock botnet is shrinking in size but its spam attacks are increasing in scale and intensity, security vendor Symantec said.
Spam levels dropped by about one-third following the recent takedown of the Rustock spambot, according to Symantec's latest Intelligence Report.
The software giant teams with the FBI and financial services industry groups to slow down a cybercrime ring that is allegedly responsible for roughly $500 million in losses.
Botnet was responsible for 18 billion spam messages a day -- about 18 percent of the world's spam -- experts tell The New York Times.
The pair, who are linked to a malware network that stole more than $100 million, are already in custody in the U.K.
The amount of spam around the globe now accounts for 70 percent of all e-mail, a sharp decline from 2009 when it accounted for 90 percent.
Provider of free domains has agreed to delete or to transfer to Microsoft all subdomains the software giant had said were tied to the Kelihos botnet.