Biblio

Despite recent regulations and growing user awareness, undesired browser tracking is increasing. In addition to cookies, browser fingerprinting is a stateless technique that exploits a device's configuration for tracking purposes. In particular, browser fingerprinting builds on attributes made available from Javascript and HTTP headers to create a unique and stable fingerprint. For example, browser plugins have been heavily exploited by state-of-the-art browser fingerprinters as a rich source of entropy. However, as browser vendors abandon plugins in favor of extensions, fingerprinters will adapt. We present FP-TESTER, an approach to automatically test the effectiveness of browser fingerprinting countermeasure extensions. We implement a testing toolkit to be used by developers to reduce browser fingerprintability. While countermeasures aim to hinder tracking by changing or blocking attributes, they may easily introduce subtle side-effects that make browsers more identifiable, rendering the extensions counterproductive. FP-TESTER reports on the side-effects introduced by the countermeasure, as well as how they impact tracking duration from a fingerprinter's point-of-view. To the best of our knowledge, FP-TESTER is the first tool to assist developers in fighting browser fingerprinting and reducing the exposure of end-users to such privacy leaks.

This paper discusses possible approaches to address the loss of user privacy when browsing the web and being tracked by websites which compute a browser fingerprint identifying the user computer. The key problem is that the current fingerprinting countermeasures are insufficient to prevent fingerprinting tracking and also frequently produce side-effects on the web browser. The advantages and disadvantages of possible countermeasures are discussed in the context of improving resistance against browser fingerprinting. Finally, using a new browser extension is proposed as the best way to inhibit fingerprinting as it could probably inhibit some of the fingerprinting techniques used and also diminish the side-effects on the user browser experience, compared with existing techniques.