A Privacy Analysis of Google and Yandex Safe Browsing

Google and Yandex Safe Browsing are popular services included in many web browsers to prevent users from visiting phishing or malware websites. If these services protect their users from losing private information, they also require that their servers receive browsing information on the very same users. In this paper, we analyze Google and Yandex Safe Browsing services from a privacy perspective. We quantify the privacy provided by these services by analyzing the possibility of re-identifying URLs visited by a client. We thereby challenge Google's privacy policy which claims thatGoogle cannot recover URLs visited by its users. Our analysis and experimental results show that Google and Yandex Safe Browsing canpotentially be used as a tool to track specific classes of individuals. Additionally, our investigations on the data currently included in Google and Yandex Safe Browsing provides a concrete set of URLs/domains that can be re-identified without much effort.