Code-Reuse Attacks for the Web

Cross-Site Scripting (XSS) is an unremitting problem for the Web. Since its initial public documentation in 2000 until now, XSS has been continuously on top of the vulnerability statistics. Even though there has been a considerable amount of research and developer education to address XSS on the source code level, the overall number of discovered XSS problems remains high. Because of this, various approaches to mitigate XSS have been proposed as a second line of defense, with HTML sanitizers, Web Application Firewalls, browser-based XSS filters, and the Content Security Policy being some prominent examples. Most of these mechanisms focus on script tags and event handlers, either by removing them from user-provided content or by preventing their script code from executing.