Law enforcement officials and security experts teamed up to beat back the Gameover Zeus botnet.

A federal grand jury in Pittsburgh has hit Evgeniy Mikhailovich Bogachev, 30, of Anapa, Russian Federation, with a 14-count indictment in connection with his alleged role as the administrator of the Gameover Zeus botnet. The indictment charges him with conspiracy, computer hacking, wire fraud, bank fraud and money laundering. He was also charged with bank fraud in Omaha in relation to his involvement with another Zeus variant known as 'Jabber Zeus.'

A separate civil injunction application filed by the U.S. in federal court in Pittsburgh accuses Bogachev of being the leader of a cyber-gang based in Russia and Ukraine that is responsible for both Gameover Zeus and Cryptolocker, a notorious piece of ransomware that has been spread by the Gameover Zeus network. The moves are the result of an international investigation that involved the FBI, Europol and a number of software companies including Microsoft, Dell SecureWorks and CrowdStrike.

"GameOver Zeus is spread through drive-by downloads, where the cybercriminals create a website that downloads malware onto any unprotected computer that visits that site," blogged Richard Domingues Boscovich, assistant general counsel for Microsoft's Digital Crimes Unit. "It is also distributed through the Cutwail spam botnet via phishing, where cybercriminals send counterfeit emails that appear to be legitimate communications from well-known businesses and organizations."

"The botnet automatically begins key logging when a user of an infected computer types into the Web browser, unwittingly giving cybercriminals access to passwords and private account information," he added. "The infected computer sends stolen data to the botnet’s C&C server, and stores it there for later use by the criminal."

Since its appearance 2011, Gameover has gone through a number of adaptations meant to make it more lethal, including the addition of a peer-to-peer component. Earlier this year, the malware was updated with a low-level driver designed to stop the malware from being easily removed and to thwart efforts at killing the Gameover process.

According to Dell SecureWorks, the Gameover Zeus was the most prevalent piece of banking malware detected by the company in 2013. That particular Trojan represented 38 percent of the company's detections last year.

The effort to dismantle Gameover Zeus also hit Cryptolocker, which began appearing about September 2013. According to the U.S. Department of Justice, security researchers have estimated that as of April 2014, the ransomware had infected more than 234,000 machines, approximately half of which are in the United States.

"This operation disrupted a global botnet that had stolen millions from businesses and consumers as well as a complex ransomware scheme that secretly encrypted hard drives and then demanded payments for giving users access to their own files and data," said Deputy Attorney General James M. Cole. "We succeeded in disabling Gameover Zeus and Cryptolocker only because we blended innovative legal and technical tactics with traditional law enforcement tools and developed strong working relationships with private industry experts and law enforcement counterparts in more than 10 countries around the world."

"The ultimate goal of the law enforcement activity is to prevent infected computers from communicating with one another, significantly weakening the criminal infrastructure," blogged Rik Ferguson of Trend Micro. "While this blow is effective, it is not permanent and we expect the malicious networks to return to their former strength within…weeks, if not days."

"This truly global operation has seen coordinated activities aimed at taking over or disrupting elements of the Command & Control infrastructure used to spread these pernicious malware families, but we cannot achieve this goal alone, every computer user has their own role to play," he added.