The notorious Zeus banking Trojan was first discovered in 2007. Pure Zeus malware is responsible for 13 percent of banking Trojan activity observed by Dell SecureWorks. Its source code was stolen and leaked in May 2011, giving nearly every banking Trojan some Zeus features. Attackers spread Zeus malware through spam campaigns and exploit toolkits to set up drive-by attacks. The Zeus botnet consists of more than 1,000 command and control servers that can send orders to more than 160,000 infected PCs. In addition to common attack capabilities, some variants of Zeus also can take screen shots and capture video.