1. Understanding Botnets: How Massive Internet Break-Ins Fuel an Underground Economy Jason Franklin and Vern Paxson

2. Abstract We study how the creation of massive networks of compromised machines fuel an underground economy. The underground market being studied is a central point for miscreant activity including identity theft, phishing, sale of compromised machines, and credit card fraud. Through extensive passive monitoring and analysis of this underground marketplace, we hope to establish connections between various facets of illegal online activities.

3. Measurement Methodology Passive monitoring and archival of Internet Relay Chat (IRC) channels –50+ monitored servers –Over 7 months of data –Over 12 million individual messages from as many as 50k individuals Limitations and Complexities –No private IRC messages –Complex underground dialect (slang) –Difficult to establish reputation S S S C C C M C IRC S C erver lient Key M onitor

4. Botnet Definition A botnet is a network of compromised machines (bots) remotely controlled by an attacker. B ot Key U ncompromised Host B Attacker B B B U U Commands Attacks

5. Underground Market Breakdown ItemTimes MentionedOffered for saleWanted Potential Bots (hacked hosts, roots, shells) 760,000500,000300,000 Exploits44,00024,00010,000 Spam Related Items750,000450,000250,000 Credit Cards & Identities 800,000340,000370,000 Compromised E-merchant Accounts 300,000170,000160,000 Scam Websites310,000200,000130,000

6. Observed Relationships and Causality Stolen Credit cards Botnets Exploits Spam Phishing & Identity Theft Scam Websites Compromised E-Merchants Credit Card Fraud Hacked Databases Identities Underground Currency Credit Cards

7. Market at a Glance Number of Days Monitored Percentage of Monitored Messages

8. Market at a Glance Number of Days Monitored Percentage of Monitored Messages

9. Vulnerability Alerts, Exploits, and Potential Bots Vertical lines represent releases of major vulnerability alert. Percentage of Monitored Messages Number of Days Monitored

10. Vulnerability Alerts, Exploits, and Potential Bots Vertical lines represent releases of major vulnerability alert. Percentage of Monitored Messages Number of Days Monitored

11. Complex Social Network Future work includes leveraging social network analysis techniques to map connections between players. “Carders” Buyers Identity Thieves Crackers Sellers Insiders Market Traders

12. Conclusion Preliminary results show that underground markets aggregate information which is otherwise difficult to observe. Monitoring underground markets may be useful as a predictor of future widespread malicious activities on the Internet. We may be able to use the market as an oracle. Future analysis of the complex relationships between market players is required.

13. Acknowledgements We would like to thank Rob Thomas of team Cymru for providing access to the IRC logs. We would also like to thank Stefan Savage, Robin Sommers, and Nick Weaver for their comments and suggestions. This research was performed while on appointment as a U.S. Department of Homeland Security (DHS) Fellow under the DHS Scholarship and Fellowship Program, a program administered by the Oak Ridge Institute for Science and education (ORISE) for DHS through an interagency agreement with the U.S Department of Energy (DOE). ORISE is managed by Oak Ridge Associated Universities under DOE contract number DE-AC05-00OR22750. All opinions expressed in this paper are the author's and do not necessarily reflect the policies and views of DHS, DOE, or ORISE. The research described here was performed at the Lawrence Berkeley National Laboratory and supported by the Director, Office of Science, Office of Workforce Development for Teachers and Scientists, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.