America's 10 most wanted

Ranked by size and strength, these are the 10 most damaging botnets in the U.S.
By Ellen Messmer, Network World


Botnet attacks are increasing, as cybercrime gangs use compromised computers to send spam, steal personal data, perpetrate click fraud and clobber Web sites in denial-of-service attacks. Here's a list of botnets, based on an estimate by security firm Damballa of botnet size and activity in the United States.

No. 1: Zeus

Compromised U.S. computers: 3.6 million

Main crime use: The Zeus Trojan uses key-logging techniques to steal sensitive data such as user names, passwords, account numbers and credit card numbers. It injects fake HTML forms into online banking login pages to steal user data.

No. 2: Koobface

Compromised U.S. computers: 2.9 million

Main crime use: This malware spreads via social networking sites MySpace and Facebook with faked messages or comments from "friends." When a user is enticed into clicking on a provided link to view a video, the user is prompted to obtain a necessary update, like a codec -- but it's really malware that can take control over the computer.

Trojan Wars

Spy Eye steals data and can then 'Kill Zeus'
By Robert McMillan, IDG News Service


An upstart Trojan horse program has decided to take on its much-larger rival by stealing data and then removing the malicious program from infected computers. Security researchers say that the relatively unknown Spy Eye toolkit added this functionality just a few days ago in a bid to displace its larger rival, known as Zeus.