Technical Report: Studying Malicious Websites and the Underground Economy on the Chinese Web

Tuesday, December 4. 2007
Together with the researchers from the Chinese Honeynet Project, we also examined the extend of malicious websites on the Chinese Web. Using high- and low-interaction honeyclients, we were able to find about 2,500 sites (1,49% of overall examined sites) that tried to compromise an unpatched system. Furthermore, we also studied the underground black market which is used to trade exploits, malware, and stolen virtual goods. Several measurements provide an insight into the black market on the Chinese Web and show that the attackers are organized pretty well. We published our findings as a technical report to share the lessons we learned.

Abstract:
The World Wide Web gains more and more popularity within China with more than 1.31 million websites on the Chinese Web in June 2007. Driven by the economic profits, cyber criminals are on the rise and use the Web to exploit innocent users. In fact, a real underground black market with thousand of participants has developed which brings together malicious users who trade exploits, malware, virtual assets, stolen credentials, and more. In this paper, we provide a detailed overview of this underground black market and present a model to describe the market. We substantiate our model with the help of measurement results within the Chinese Web. First, we show that the amount of virtual assets traded on this underground market is huge. Second, our research proofs that a significant amount of websites within China's part of the Web are malicious: our measurements reveal that about 1.49% of the examined sites contain some kind of malicious content.


The complete report is available as TR-2007-011.
Posted by Thorsten Holz in honeynets, malware, paper at 08:16 | Comments (2) | Trackbacks (0)

Technical Report: Characterizing the IRC-based Botnet Phenomenon

Monday, December 3. 2007
Together with a few researchers from China, we studied IRC-based botnets in order to understand the extent of this phenomenon. Using different kinds of honeypots and several sensors deployed across different regions in China, we were able to collect thousands of bot binaries. With the help of a behavior-based analysis mechanism similar to CWSandbox, we could extract the Command & Control (C&C) server in an automated way. In a third step, we used this information to connect to the actual C&C server and passively monitored the activity in the channel. Furthermore, we also actively probed the C&C servers to find out other characteristics of these machines. The complete setup and our results are described in a technical report we just published.

Abstract:
Botnets, networks of compromised machines that can be remotely controlled by an attacker, are one of the most common attack platforms nowadays. They can, for example, be used to launch distributed denial-of-service (DDoS) attacks, steal sensitive information, or send spam emails. A long-term measurement study of botnet activities is useful as a basis for further research on global botnet mitigation and disruption techniques. We have built a distributed and fully-automated botnet measurement system which allows us to collect data on the botnet activity we observe in China. Based on the analysis of tracking records of 3,290 IRC-based botnets during a period of almost twelve months, this paper presents several novel results of botnet activities which can only be measured via long-term easurements. These include. amongst others, botnet lifetime, botnet discovery trends and distributions, command and control channel distributions, botnet size and end-host distributions. Furthermore, our measurements confirm and extend several previous results from this area.

Our results show that the botnet problem is of global scale, with a scattered distribution of the control infrastructure and also a scattered distribution of the victims. Furthermore, the control infrastructure itself is rather flexible, with an average lifetime of a Command & Control server of about 54 days. These results can also leverage research in the area of botnet detection, mitigation, and disruption: only by understanding the problem in detail, we can develop efficient counter measures.


The complete report is available as TR-2007-010. And more information regarding the Chinese Honeynet Project is available at the website of the Artemis Project.
Posted by Thorsten Holz in honeynets, malware, paper at 14:02 | Comments (0) | Trackback (1)
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