DOMPurify bypass: XSS via HTML namespace confusion
How to people do proper XSS protection and more importantly validate against it?It's effectively a manual process of calling appropriate escaping (html, css, js) at every dynamic output site. Ensuring you are doing it 100% in thousands if not millions of calls is daunting.I have seen security tools crawling your app and using payload to test for vulnerability which sounds nice in theory but in a really complex application where you need to understand the business rules to even crawl the whole application (not get caught up on validation/error) how do people ensure that?