Revisiting Circuit Clogging Attacks on Tor

摘要: Tor is a popular anonymity-providing network used by over 500,000 users daily. The made up of volunteer relays. To anonymously connect to server, user first creates circuit, consisting three relays, and routes traffic through these proxies before connecting the server. client thus hidden from server proxies. If could be identified, anonymity would reduced. One particular way identifying relays in circuit perform clogging attack. This attack requires malicious (malicious content, such as an advertising frame, can hosted on server). alternates between sending bursts data little traffic. During burst period, will take longer relay due increase processing time for extra messages. are continuously monitored latency probes, indicates that this likely being circuit. We show, experiments real network, identified. A detection scheme also proposed clients determine whether happening. costs both mechanism small feasible current network.