Microsoft is offering a $250,000 reward for information leading to the arrest of those who controlled Rustock, a recently dismantled botnet that in its heyday was one of the biggest sources of illegal spam.
Monday's announcement of the bounty comes four months after Microsoft waged a novel campaign to take down Rustock, which enslaved an estimated 1 million PCs. The number of infected machines has been cut in half since that time, and Microsoft has already taken out ads in Russian newspapers in an attempt to track down the operators of the notorious botnet.
Now Microsoft is redoubling those efforts with the promise of the hefty quarter-million dollar bounty to anyone who can help Microsoft and law enforcement officials identify and catch the perps.
“This reward offer stems from Microsoft’s recognition that the Rustock botnet is responsible for a number of criminal activities and serves to underscore our commitment to tracking down those behind it,” Richard Boscovich, a senior attorney in the Microsoft Digital Crimes Unit, wrote in a blog post. “While the primary goal for our legal and technical operation has been to stop and disrupt the threat that Rustock has posed for everyone affected by it, we also believe the Rustock bot-herders should be held accountable for their actions.”
According to Microsoft, Rustock was at times capable of sending 30 billion spam messages per day. Among other things, it pitched discounted pharmaceutical drugs that were fakes or unlicensed, posing a hazard to those who used them.
The March takedown of the botnet wielded court orders that allowed authorities to seize servers at five hosting providers that were used to administer the sophisticated botnet. Although the IP addresses hardwired into the underlying malware have been severed, hundreds of thousands of infected PCs have yet to be cleaned, Boscovich said.
The Rustock takedown came a little more than a year after Microsoft used similar tactics to dismantle another notorious botnet known as Waledac. In April, federal authorities borrowed many of the same techniques to shut down the Coreflood botnet. The Coreflood takedown went even further by giving the feds legal permission to establish a substitute control channel that temporarily disabled the underlying malware running on hundreds of thousands of infected end-user computers.
A PDF of Microsoft's official notice is here.