Abstract
This paper describes a new attack on the anonymity of web browsing with Tor. The attack tricks a user’s web browser into sending a distinctive signal over the Tor network that can be detected using traffic analysis. It is delivered by a malicious exit node using a man-in-the-middle attack on HTTP. Both the attack and the traffic analysis can be performed by an adversary with limited resources. While the attack can only succeed if the attacker controls one of the victim’s entry guards, the method reduces the time required for a traffic analysis attack on Tor from O(nk) to O(n + k), where n is the number of exit nodes and k is the number of entry guards. This paper presents techniques that exploit the Tor exit policy system to greatly simplify the traffic analysis. The fundamental vulnerability exposed by this paper is not specific to Tor but rather to the problem of anonymous web browsing itself. This paper also describes a related attack on users who toggle the use of Tor with the popular Firefox extension Torbutton.
Access provided by Autonomous University of Puebla. Download to read the full chapter text
Chapter PDF
Similar content being viewed by others
Keywords
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
References
Chaum, D.: Untraceable electronic mail, return addresses, and digital pseudonyms. Communications of the ACM 24(2) (February 1981)
Christensen, A., et al.: Practical Onion Hacking: Find the real address of Tor clients. FortConsult (October 2006), http://www.fortconsult.net/images/pdf/Practical_Onion_Hacking.pdf
Clark, D.: Design Philosophy of the DARPA Internet Protocols. In: Proceedings of the ACM Special Interest Group on Data Communications, pp. 106–114. ACM Press, New York (1988)
Dingledine, R.: Tor: anonymity (November 2006), http://tor.eff.org/
Dingledine, R., Mathewson, N., Syverson, P.: Tor: The Second-Generation Onion Router. In: Proceedings of the 13th USENIX Security Symposium (August 2004)
Douceur, J.: The Sybil Attack. In: Druschel, P., Kaashoek, M.F., Rowstron, A. (eds.) IPTPS 2002. LNCS, vol. 2429, Springer, Heidelberg (2002)
Hintz, A.: Fingerprinting Websites Using Traffic Analysis. In: Proceedings of Privacy Enhancing Technologies workshop (April 2002)
Levine, B.N., Reiter, M., Wang, C., Wright, M.: Timing Attacks in Low-Latency Mix Systems (extended abstract). In: Proc. Financial Cryptography, pp. 251–265 (February 2004)
Liberatore, M., Levine, B.N.: Inferring the source of encrypted HTTP connections. In: Proceedings of the 13th ACM conference on Computer and communications security, ACM Press, New York (2006)
Martin, K.: AOL search data identified individuals. SecurityFocus (August 2006), http://www.securityfocus.com/brief/277
Murdoch, S.J., Danezis, G.: Low-Cost Traffic Analysis of Tor. In: Proceedings of the 2005 IEEE Symposium on Security and Privacy (May 2005)
Øverlier, L., Syverson, P.: Locating Hidden Servers. In: Proceedings of the 2006 IEEE Symposium on Security and Privacy (May 2006)
Raymond, J.: Traffic Analysis: Protocols, Attacks, Design Issues, and Open Problems. In: Proceedings of Designing Privacy Enhancing Technologies: Workshop on Design Issues in Anonymity and Unobservability, pp. 10–29 (July 2000)
Serjantov, A., Sewell, P.: Passive Attack Analysis for Connection-Based Anonymity Systems. In: Snekkenes, E., Gollmann, D. (eds.) ESORICS 2003. LNCS, vol. 2808, pp. 116–131. Springer, Heidelberg (2003)
Syverson, P., Tsudik, G., Reed, M., Landwehr, C.: Towards an Analysis of Onion Routing Security. In: Workshop on Design Issues in Anonymity and Unobservability (July 2000)
Wright, M., Adler, M., Levine, B.N., Shields, C.: An Analysis of the Degradation of Anonymous Protocols. In: Proceedings of the ISOC Network and Distributed System Security Symposium (NDSS), pp. 38–50 (February 2002)
Wright, M., Adler, M., Levine, B.N., Shields, C.: Defending Anonymous Communication Against Passive Logging Attacks. In: Proceedings of the 2003 IEEE Symposium on Security and Privacy (May 2003)
Wright, M., Adler, M., Levine, B.N., Shields, C.: The predecessor attack: An analysis of a threat to anonymous communications systems. In: ACM Trans. Inf. Syst. Secur., pp. 489–522 (2004)
Squires, S.: Firefox Add-ons: Torbutton (February 2007), https://addons.mozilla.org/firefox/2275/
TheOnionRouter/TorFAQ (November 2006), http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 2007 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Abbott, T.G., Lai, K.J., Lieberman, M.R., Price, E.C. (2007). Browser-Based Attacks on Tor. In: Borisov, N., Golle, P. (eds) Privacy Enhancing Technologies. PET 2007. Lecture Notes in Computer Science, vol 4776. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-75551-7_12
Download citation
DOI: https://doi.org/10.1007/978-3-540-75551-7_12
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-75550-0
Online ISBN: 978-3-540-75551-7
eBook Packages: Computer ScienceComputer Science (R0)