Large-Scale Measurement and Real-World Mitigation of Web Browser Fingerprinting in the Wild

Mozilla researchers measured browser fingerprinting across nearly 25 million Firefox release users and found that a small set of high-impact characteristics, rather than the accumulation of many measurements, drives most uniqueness. The study, led by Tom Ritter and colleagues at Mozilla, the University of Toronto and UC San Diego, used privacy-preserving telemetry including OHTTP so no individual user could be identified. Mozilla has released the paper, appendix data, aggregate datasets and analysis code, plus an interactive test letting users compare their own browser against the measured population. Next, watch adoption of the Firefox 143 mitigations and whether the measured uniqueness gains hold against commercial fingerprinters as protections are layered on.