A company dedicated to provide web security warned recently that Zeus, the virus, which steals details through online banking from the infected computers, has become more powerful than before.

According to Trusteer, one out of every 3000 of 5.5m computers has Trojan virus, monitored in US and UK. The company claims that computers on which Internet Explorer and Firefox web browsers are used can be infected with Zeus 1.6.

This is a kind of malware, which steals login information by tracking keystrokes, when the infected users are on the list of targeted websites. Usually, these websites belong to banks and other financial institutions. The data of the users is then received by remote server, so that it can be sold to and used by cyber criminals.

Chief Technology Officer of Trusteer, Amit Klein, says that this latest version of Zeus has led to a significant rise in the fraud losses, as around 30% of the Internet savvy people make their online financial transactions through Firefox. The infection is spreading widespread much faster than before.

During March 2010, several parts of the C&C system (command and control system) for Zeus botnet got destroyed when the ISP of Kazakhstan was cut off. The ISP was used for administering the C&C system. However, springing up to a different place is not difficult for the malware controllers. As a result, toolkits used for assembling the botnets have become available in the black market.

Dr. JD Marsters, University of Southampton, Department of Electronics & Computer Science, says that people can buy accessibility to such systems via underground chat rooms. “It’s a game of cat and mouse between anti-virus vendors and botnet developers,” he says.

He also advises that the computer users should keep their anti-virus software and their operating systems up to date, so that they can remain protected from this dreadful virus.