What Storage? An Empirical Analysis of Web Storage in the Wild

Zubair Ahmad (Università Ca’ Foscari Venezia), Samuele Casarin (Università Ca’ Foscari Venezia), and Stefano Calzavara (Università Ca’ Foscari Venezia)

In this paper we perform the first 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 5k. 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. This motivates the need for further research on the security and privacy implications of web storage content.