An Empirical Analysis of Web Storage and Its Applications to Web Tracking

Abstract

In this article, we present a large-scale empirical analysis of the use of web storage in the wild.By using dynamic taint tracking at the level of JavaScript and by performing an automated classification of the detected information flows, we shed light on the key characteristics of web storage uses in the Tranco Top 10k. Our analysis shows that web storage is routinely accessed by third parties, including known web trackers, who are particularly eager to have both read and write access to persistent web storage information. We then deep dive in web tracking as a prominent case study: our analysis shows that web storage is not yet as popular as cookies for tracking purposes; however, taint tracking is useful to detect potential new trackers not included in standard filter lists. Moreover, we observe that many websites do not comply with the General Data Protection Regulation directives when it comes to their use of web storage.