Abusing JSONP with Rosetta Flash
L33tdawg: Early bird registration rates for #HITB2014KUL ends on the 1st of August... What are you waiting for?
In this blog post I present Rosetta Flash, a tool for converting any SWF file to one composed of only alphanumeric characters in order to abuse JSONP endpoints, making a victim perform arbitrary requests to the domain with the vulnerable endpoint and exfiltrate potentially sensitive data, not limited to JSONP responses, to an attacker-controlled site. This is a CSRF bypassing Same Origin Policy.
High profile Google domains (accounts.google.com, www., books., maps., etc.) and YouTube were vulnerable and have been recently fixed. Twitter, Instagram, Tumblr, Olark and eBay still have vulnerable JSONP endpoints at the time of writing this blog post (but Adobe pushed a fix in the latest Flash Player, see paragraph Mitigations and fix). This is a well known issue in the infosec community, but so far no public tools for generating arbitrary ASCII-only, or, even better, alphanum only, valid SWF files have been presented. This led websites owners and even big players in the industry to postpone any mitigation until a credible proof of concept was provided. So, that moment has come :)
I will present this vulnerability at Hack In The Box: Malaysia this October, and the Rosetta Flash technology will be featured in the next PoC||GTFO release.
