Cross-Site Search Attacks: Unauthorized Queries over Private Data

Cross-site search attacks allow a rogue website to expose private, sensitive user-information from web applications. The attacker exploits timing and other side channels to extract the information, using cleverly-designed cross-site queries.

In this work, we present a systematic approach to the study of cross-site search attacks. We begin with a comprehensive taxonomy, clarifying the relationships between different types of cross-site search attacks, as well as relationships to other attacks. We then present, analyze, and compare cross-site search attacks; We present new attacks that have improved efficiency and can circumvent browser defenses, and compare to already-published attacks. We developed and present a reproducibility framework, which allows study and evaluation of different cross-site attacks and defenses.

We also discuss defenses against cross-site search attacks, for both browsers and servers. We argue that server-based defenses are essential, including restricting cross-site search requests.