I often talk about cross-site scripting (XSS), and that’s partly because I think it’s a pretty interesting type of vulnerability that many developers tend to overlook. It can be quite dangerous, but can also be quite misunderstood. For one thing, the name can be misleading: exploiting XSS does not always involve scripting, and the proliferation of web technologies has taken XSS issues beyond the browser. One example of script-less cross-site scripting affected some high-profile MySpace users in 2007. Attackers were able to inject HTML into celebrity MySpace pages, but the service filtered out typical <script> payloads. Seemingly innocent <a> links were allowed, though, and adding a bit of CSS allowed one to create an invisible link that covered the entire[…]