Researchers at Trustwave have discovered a new use for botnets: emptying bitcoin wallets. Reuters reports that a single botnet has used the Pony botnet controller to empty 85 different bitcoin wallets associated with infected machines, making off with an undisclosed amount. Trustwave successfully disrupted the botnet, but the group behind the attacks is still at large.

The group performed the attacks using the Pony Botnet Controller, a known method of attack that one group used to steal more than two million passwords last year. These latest attacks are noteworthy because, rather than going after credentials or details for identity theft, Bitcoin allows criminals to go straight for the cash and make a clean getaway. While phishing thefts have been reported before, this is the first known attack using botnets to empty wallets. "It is the first time we saw such a widespread presence of this type of malware," Trustwave researcher Ziv Mador told Reuters. "It was on hundreds of thousands of machines."