Fingerprintability of WebRTC
This addresses the problem of Internet censorship for users relying on tools like Snowflake, but is incremental as it analyzes existing vulnerabilities.
The study investigated WebRTC's vulnerability to fingerprinting as a censorship circumvention tool, finding that implementation differences allow distinguishing circumvention uses from ordinary ones, with pitfalls indicating resistance is non-trivial.
We examine WebRTC's suitability as a means of Internet censorship circumvention. WebRTC is a framework and suite of protocols for peer-to-peer communication between web browsers. We analyze the implementation differences in instantiations of WebRTC that make it possible to "fingerprint" implementations--potentially distinguishing circumvention-related uses from ordinary ones. This question is relevant to Snowflake, an upcoming circumvention system that uses WebRTC to turn web browsers into temporary peer-to-peer proxies. We conduct a manual analysis of WebRTC-using applications in order to map the space of distinguishing implementation features. We run a fingerprinting script on a day's worth of network traffic in order to quantify WebRTC's prevalence and diversity. Throughout, we find pitfalls that indicate that resisting fingerprinting in WebRTC is likely to be non-trivial.