Variants of the ZeuS (ZBOT) Trojan were the most distributed pieces of malware, by spam, in August 2013, Trend Micro reports.
According to experts, the ZeuS malware was identified in 23% of all the malicious attachments found in spam emails. ZeuS is followed by Fareit (19%), Mytob (9%), Tepper (8%) and Wauchos (7%).
The spam notifications used to distribute ZeuS and Fareit stand out because they usually replicate legitimate messages that appear to come from well-known companies.
When it’s installed on a computer, ZeuS waits for the victim to visit certain banking websites. When such a site is visited, a malicious page is injected in an effort to trick the user into handing over sensitive personal and financial information.
Fareit, on the other hand, is designed to steal email and FTP login credentials. It’s also capable of downloading other threats onto the infected device.