Security research company FireEye claims to have successfully brought down a botnet believed to have been responsible for nearly a fifth of the world's spam emails.
FireEye reported taking the Grum botnet down following a joint operation with spam-tracking service SpamHaus and local internet service providers (ISPs).
The botnet was reportedly killed after the team shutdown Grum's control servers, which FireEye claims were mainly based in Panama, Russia and Ukraine.
"Grum's takedown resulted from the efforts of many individuals," wrote Atif Mushtaq, a security researcher with FireEye.
"This collaboration is sending a strong message to all the spammers: stop sending us spam. We don't need your cheap Viagra or fake Rolex."
Grum is believed to have been the world's third largest botnet, with researchers estimating it was spitting out 18 billion spam messages a day at its peak.
Mushtaq went on to claim that the success of the joint operation is proof that companies and government agencies must pull together to fight cyber crime.
"When the appropriate channels are used, even ISPs within Russia and Ukraine can be pressured to end their cooperation with bot herders. There are no longer any safe havens," wrote Mushtaq.
"Most of the spam botnets that used to keep their [command and control servers] in the USA and Europe have moved to countries like Panama, Russia, and Ukraine thinking that no one can touch them in these comfort zones. We have proven them wrong."
Prior to Mushtaq's claim, Microsoft Trustworthy Computing director Tim Rains had issued a warning claiming Europe's cyber crime business is booming.