Web Application Exploits and Defenses(google-gruyere.appspot.com) |
Web Application Exploits and Defenses(google-gruyere.appspot.com) |
https://github.com/cure53/XSSChallengeWiki/wiki
https://sites.google.com/site/infosecrocks/ (this links to some of the other stuff I mentioned)
There's also these 2 advanced XSS challenges:
I'm not sure if they're still functional, I think some of their solutions require functionality that browsers have since changed.
You might also want to check out the Youtube channel Live Overflow: