It is transmitted by drive-by downloads and phishing.
When it's installed on a host computer, it tries to scare the user with pop-up messages.
In late 2010, the creator of Zeus sold the source code to the creator of SpyEye.
Zeus is very difficult to detect with old antivirus programs and other old security software as it hides itself with powerful stealth techniques. It is considered that this is the primary reason why the Zeus trojan has become the most powerful botnet on the Internet. Zeus has infected 3.6 million PCs in the United States in 2009.
However, new and updated antivirus software such as Malwarebytes are able to easily detect and delete Zeus.