The Zeus botnet is one of the most prolific bots in the wild and in the media. Lately there has been quite a few reports on the aspects surrounding Zeus, such as new research and the Troyak takedown. Unfortunately, in many of the reports there is a recurring incorrectness. The reality is that there are many, many different different Zeus botnets all maintained by different cyber criminals. The amount of unique Zeus-Botnets is likely to be in the hundreds. The cyber criminals behind the Zeus-Zeus bot will sell it to anyone who can then start their own unique.
Source: https://threatpost.com/which-real-zeus-botnet-043010/73901/