Schneier on Security

Researchers Hijack a Botnet

A bunch of researchers at the University of California Santa Barbara took control of a botnet for ten days, and learned a lot about how botnets work:

The botnet in question is controlled by Torpig (also known as Sinowal), a malware program that aims to gather personal and financial information from Windows users. The researchers gained control of the Torpig botnet by exploiting a weakness in the way the bots try to locate their commands and control servers—the bots would generate a list of domains that they planned to contact next, but not all of those domains were registered yet. The researchers then registered the domains that the bots would resolve, and then set up servers where the bots could connect to find their commands. This method lasted for a full ten days before the botnet’s controllers updated the system and cut the observation short.

During that time, however, UCSB’s researchers were able to gather massive amounts of information on how the botnet functions as well as what kind of information it’s gathering. Almost 300,000 unique login credentials were gathered over the time the researchers controlled the botnet, including 56,000 passwords gathered in a single hour using “simple replacement rules” and a password cracker. They found that 28 percent of victims reused their credentials for accessing 368,501 websites, making it an easy task for scammers to gather further personal information. The researchers noted that they were able to read through hundreds of e-mail, forum, and chat messages gathered by Torpig that “often contain detailed (and private) descriptions of the lives of their authors.”

Here’s the paper:

Abstract:

Botnets, networks of malware-infected machines that are controlled by an adversary, are the root cause of a large number of security threats on the Internet. A particularly sophisticated and insidious type of bot is Torpig, a malware program that is designed to harvest sensitive information (such as bank account and credit card data) from its victims. In this paper, we report on our efforts to take control of the Torpig botnet for ten days. Over this period, we observed more than 180 thousand infections and recorded more than 70 GB of data that the bots collected. While botnets have been “hijacked” before, the Torpig botnet exhibits certain properties that make the analysis of the data particularly interesting. First, it is possible (with reasonable accuracy) to identify unique bot infections and relate that number to the more than 1.2 million IP addresses that contacted our command and control server. This shows that botnet estimates that are based on IP addresses are likely to report inflated numbers. Second, the Torpig botnet is large, targets a variety of applications, and gathers a rich and diverse set of information from the infected victims. This opens the possibility to perform interesting data analysis that goes well beyond simply counting the number of stolen credit cards.

Another article.

Tags: academic papers, botnets, crime, cybercrime, fraud, malware, passwords, privacy, scams

Posted on May 11, 2009 at 6:56 AM • 21 Comments