A New Cell-Counting-Based Attack Against Tor

Abstract—Various low-latency anonymous communication systems such as Tor and Anonymizer have been designed to provide anonymity service for users. In order to hide the communication of users, most of the anonymity systems pack the application data into equal-sized cells (e.g., 512 B for Tor, a known real-world, circuit-based, low-latency anonymous communication network). Via extensive experiments on Tor, we found that the size of IP packets in the Tor network can be very dynamic because a cell is an application concept and the IP layer may repack cells. Based on this finding, we investigate a new cell-counting-based attack against Tor, which allows the attacker to confirm anonymous communication relationship among users very quickly. In this attack, by marginally varying the number of cells in the target traffic at the malicious exit onion router, the attacker can embed a secret signal into the variation of cell counter of the target traffic. The embedded signal will be carried a...

• Type: Journal
• Year: 2012
• Where: TON
• Authors: Zhen Ling, Junzhou Luo, Wei Yu, Xinwen Fu, Dong Xuan, Weijia Jia
• Keywords: Communication Sessions, Networking Editor, Onion Router, Programming Languages, TON 2012