The Elephant in the Background: A Quantitative Approachto Empower Users Against Web Browser Fingerprinting

Tracking users is a ubiquitous practice on the web today. User activity is recorded and analyzed on a large scale to create personalized products, forecast future behavior, and prevent online fraud. While HTTP cookies have been the weapon of choice so far, new and more pervasive techniques such as browser fingerprinting are gaining traction. This paper describes how users can be empowered against fingerprinting by showing them when, how, and who is tracking them. To this end, we conduct a systematic analysis of various fingerprinting tools to create FPMON: a browser extension to measure and rate fingerprinting activity on any website in real-time. With FPMON, we evaluate the 10k most popular websites to i) study the pervasiveness of fingerprinting; ii) review the latest countermeasures; and iii) identify the networks that foster the use of fingerprinting. Our evaluations reveal that i) fingerprinters subvert privacy regulations; ii) they are present on privacy-sensitive websites (insurance, finances, NGOs); and iii) current countermeasures cannot sufficiently protect users. Hence, we publish FPMON as a free browser extension to empower users against this growing threat.