An undercover operation by Dutch and Russian authorities resulted in the arrest of Georg Avanesov earlier this week. Avanesov had allegedly been running a network of hacked computers around the world, typically referred to as a botnet, for over a decade. According to a source close to law enforcement, the 27-year-old made millions during that time frame.

Avanesov is suspected to be one of the curators of Bredolab, a trojan horse usually distributed through email attachments or downloaded inadvertently through browser security holes. Once infected, a computer running Bredolab can be used to download and execute files from the Internet. Dutch prosecutors believe that Avanesov made up to €100,000 ($138,950) a month from renting and selling part of his botnet to other cybercriminals for limited periods of time. They in turn used it to send their own spam or mine the PCs for personal data and files.

Avanesov was able to sell parts of the botnet off "because it was very easy for him to extend the botnet again," by infecting more PCs, a Public Prosecution Service in Rotterdam spokesperson told ComputerWorld. At its peak, Bredolab could send billions of spam e-mail messages in a month and is accounted for infecting millions of computers in a relatively short span of time.