Low-Resource Routing Attacks Against Tor

Tor has become one of the most popular overlay networks for anonymizing TCP traffic. Its popularity is due in part to its perceived strong anonymity properties and its relatively low latency service. Low latency is achieved through Tor's ability to balance the traffic load by optimizing Tor router selection to probabilistically favor routers with high-bandwidth capabilities. The authors investigate how Tor's routing optimizations impact its ability to provide strong anonymity. Through experiments conducted on PlanetLab, they show the extent to which routing performance optimizations have left the system vulnerable to end-to-end traffic analysis attacks from non-global adversaries with minimal resources.