Bsides Cymru 2024

Client-Side Attacks in a Post-XSS World
04-27, 14:40–15:10 (Europe/London), Sophia Room - Track 2

The web platform's openness and composability provide many benefits. Yet, the ability for websites to interact with each other has provided many opportunities for attacks that abuse the core principles of the web. With advancements in web technologies, it might seem like we are entering a post-XSS world. But modern client-side security is so much more than just traditional XSS and CSRF!


With the evolution of web frameworks and browsers, Cross-Site Scripting (XSS) and Cross-Site Request Forgery (CSRF) have become increasingly rare. In response, new classes of client-side vulnerabilities have emerged - DOM clobbering, XS-Leaks and client-side path traversals are just a few examples.

In this talk, we will explore the merits and potential pitfalls of various protections against XSS and CSRF, newer classes of client-side attacks and some real-world examples of their applications.

Zayne is a Computer Science student at the University of Cambridge. He is an avid security researcher and CTF player. He holds industry certificates such as the OSWE and OSCP, and has previously worked in TikTok's security team. In his free time, he hunts for bugs on the HackerOne platform, and plays CTFs with Blue Water, one of the top global CTF teams.