Monday, September 23, 2013

Exploiting EasyXDM part 1: Not the usual Flash XSS

tldr: You're using easyXDM? Upgrade NOW. Otherwise - read up on exploiting difficult Flash vulnerabilities in practice.

Secure cross-domain communication is hard enough, but it's a piece of cake compared to making it work in legacy browsers. One popular library that tries to handle all the quirks and even builds an RPC framework is easyXDM.

But this is not an advertisement. As usual, you only get to hear about easyXDM here, because I found some interesting vulnerabilities. Combined, those allow me to XSS websites using that library. Certain conditions apply. As exploiting the subject matter is quite complex, I decided to split the post into two parts, this being the first one.