Can I Take Your Subdomain? Exploring Related-Domain Attacks in the Modern Web
This research addresses a previously under-explored security threat for web application developers and users, specifically concerning related-domain attacks.
This paper defines and quantifies the threats posed by related-domain attackers to web application security, showing how capabilities acquired through various attack vectors can be abused. A large-scale measurement on the top 50k Tranco domains revealed vulnerabilities in 887 sites.
Related-domain attackers control a sibling domain of their target web application, e.g., as the result of a subdomain takeover. Despite their additional power over traditional web attackers, related-domain attackers received only limited attention by the research community. In this paper we define and quantify for the first time the threats that related-domain attackers pose to web application security. In particular, we first clarify the capabilities that related-domain attackers can acquire through different attack vectors, showing that different instances of the related-domain attacker concept are worth attention. We then study how these capabilities can be abused to compromise web application security by focusing on different angles, including: cookies, CSP, CORS, postMessage and domain relaxation. By building on this framework, we report on a large-scale security measurement on the top 50k domains from the Tranco list that led to the discovery of vulnerabilities in 887 sites, where we quantified the threats posed by related-domain attackers to popular web applications.