Researchers: Botnet infects thousands of government computers

Company officials say nearly 2 million computers have been infected — some on U.S. government networks.

SAN FRANCISCO — Researchers at Finjan Software Inc. reported today the discovery of a new botnet of nearly 2 million infected computers — many of them in U.S. government networks.

The botnet, apparently controlled from Ukraine, includes IP addresses from 77 government domains mainly in the United States, said Ophir Shalitin, Finjan’s marketing director, at the RSA security conference. Fifty-one are U.S. government domains, he added. “It is being spread primarily through legitimate Web sites that have been infected.”

The Trojan responsible for the infections, named Seneka, appears to be targeting English-language Web sites. The United States has the most  infections, with 45 percent of the total number of compromised computers,  followed by the United Kingdom with 6 percent and Canada with 4 percent.

“We have acted on this,” Shalitin said. Finjan has informed law enforcement agencies in the United States and the United Kingdom, as well as organizations with large infections. There have been immediately visible results from that notification, he said. “The rate of infections is high, and more people are becoming infected.”

Finjan said data on the botnet’s command and control server showed 1.95 million infections as of March 18.

“We have seen this number increasing during our research, on an hourly basis,” the company said.

“Botnet” is the term for a network of compromised computers that can be remotely controlled from a central server or servers. Once a computer is infected, additional malicious code can be downloaded to it, along with commands to gather information, launch attacks or send spam. Botnets can be rented in whole or in part by their controllers to online criminals.

“To what extent information has been collected, I don’t know,” Shalitin said. But “we have a lot of information on what kind of malware has been used.”

Researchers found a log of three dozen files that had been loaded onto infected computers. “Overall, the cyber gang can remotely execute anything it likes on the infected computers,” the company said.

The botnet was discovered when open folders on a server hosted in Ukraine were found by researchers at Finjan’s Malicious Code Research Center. The Seneka Trojan exploits a variety of vulnerabilities to infect legitimate Web sites, then scans visiting browsers for multiple vulnerabilities through which to infect them.

One Trojan that was loaded onto bots was discovered by only four of 39 antivirus products that it was tested against.

Seneka is not using zero-day attacks to infect Web sites and computers but instead exploits known vulnerabilities for which patches are available, Shalitin said. This means that both the client and server side can protect themselves by updating patches. Web sites also can use content inspection tools to ensure that malicious code is not making its way onto sites and engaging in unauthorized behavior.