1. Gameover Zeus
Gameover, which was first detected in 2011, is responsible for 38 percent of the banking Trojans detected in the space. It spreads through email attachments and drive-by downloads. Gameover is tightly controlled and available to a small segment of the criminal economy. It also uses peer-to-peer communication techniques to mask the location of its command and control servers and drop-off points. Dell SecureWorks researchers call further development of the botnet "extremely focused and driven by a small group of threat actors." Interestingly, those behind Gameover Zeus have been observed using distributed denial-of-service attacks as a diversion tactic to prevent victims from being able to log into their accounts.