Injecting the script tag into XML
Tuesday, 9 October 2007
Firefox is now the browser I like hacking, there’s just so much stuff it can do. I simply don’t have enough time to explore everything, but what I have found was some very interesting XML behavior. I was helping Ronald a while back with a Firefox chrome security flaw and we discussed on slackers that some XML entities in Firefox contain sensitive information which it is possible to read using XHR.
I thought of what other interesting things I could do with XML entities and I found a way of injecting script tags using them. This could have implications if you offer a HTML upload service but you filter out dangerous tags for example. The proof of concept is very basic but displays the method clearly.