Security

Home page of the Golden Cash network.

(Credit: Finjan)

Researchers at security firm Finjan said on Wednesday that they have uncovered an underground botnet-leasing network where cyber criminals can pay $5 to $100 to install malware on 1,000 PCs for things like stealing data and sending spam.

The Golden Cash network, dubbed "Your money-making machine" on its home page, sells access to botnets comprised of thousands of compromised PCs to cyber criminals for custom malware spreading jobs, according to issue 2 of the Cybercrime Intelligence Report for 2009.

Here's how it works: a cyber criminal creates a botnet by hiding malicious code in a legitimate Web site that is used to turn Web surfing PCs into zombies. The code, typically an iFrame, points the PCs to a separate Web site where they are then infected with a Trojan backdoor that reports back to the Golden Cash command and control server.

In order to increase the number of botnets, the Golden Cash server installs an FTP (file transfer protocol) grabber on new zombies to steal credentials used by the computers to run Web sites, giving the server control over additional legitimate Web sites. Approximately 100,000 domains, including corporate domains from around the world, were identified among the stolen FTP credentials under Golden Cash's control, according to the report.

Customers pay for the ability to install different types of malware on the Golden Cash bots, which are recycled for new jobs and new customers afterward. Prices are higher for compromised PCs in western countries, the report said.

"This advanced trading platform marks a new milestone in the cybercrime evolution," Finjan said in a statement.

More technical analysis is available on Finjan's Malicious Code Research Center blog, including the fact that the command and control server is hosted in Texas, the registrant country is China and the "proxy" Web site that tunnels traffic to the command and control server is hosted in Krasnodar, Russia.