Posted by Virus Bulletin on Jun 5, 2014
Coordinated effort against gang that's also behind CryptoLocker ransomware.
A large, coordinated effort involving law enforcement, security vendors and various security researchers, has caused serious disruption to both the GameOver Zeus botnet and the CryptoLocker ransomware.
GameOver Zeus is a particularly sophisticated variant of the Zeus trojan. Rather than a centralised command and control infrastructure, it uses peer-to-peer (P2P) technology to keep its infrastructure hidden, and thus make takedowns a lot harder - hence it is occasionally referred to as P2P Zeus.
The trojan's main purpose is to steal banking credentials - something which has been rather lucrative for the criminals behind the botnet: the FBI estimates GameOver Zeus to have been responsible for over $100m in losses.
Gary Warner, from the University of Alabama at Birmingham, writes about the criminal complaint against Evgeniy Mikhailovich Bogachev, a 30-year-old Russian, as well as several as-yet unidentified hackers. They are being charged with wire fraud, bank fraud and unauthorized interception of electronic communications.
Seemingly, the revenue GameOver Zeus generated for the criminals wasn't satisfactory, as the same gang was also behind the distribution of the infamous CryptoLocker trojan, a particularly nasty piece of ransomware which uses strong file encryption to encrypt files on a victim's computer then demands a ransom to decrypt them.
The takedown of the botnet appears to have been successful so far, as can been seen from statistics published by the Polish CERT:
Meanwhile, Danish firm Heimdal Security says that the number of new CryptoLocker infections has dropped from 8,000 a day to almost zero.
Whether the disruption to GameOver Zeus and CryptoLocker will be permanent remains to be seen. But the involvement of many researchers means that one mistake made during previous takedowns may have been avoided: in their efforts to disrupt botnets' infrastructures, past takedowns have used a broad sweep, and in doing so have also taken down 'sinkholes' operated by security researchers and vendors, causing unnecessary disruption and a lot of frustration. This time, as a number of security researchers were actively involved in the effort, it is less likely that such mistakes were made.
Botnets tend to evolve quickly, but so do takedowns. And that is a very good thing.
Posted on 05 June 2014 by Martijn Grooten