[Full-disclosure] Fwd: Web 2.0 backdoors made easy with MSIE & XMLHttpRequest

Giorgio Fedon giorgio.fedon at gmail.com
Sun Feb 4 00:26:48 GMT 2007


During the lecture we presented at 23C3 "Subverting Ajax" we focused on many
topics about Ajax client side attacks.
One of these was called Cross Domain Scripting (Aka XDS or AICS) that
exploited a Http Request Splitting Vulnerability to bypass DOM restrictions
and  inject in realtime javascript code during the user browsing session.

This kind of attack relies on:
1) Request Splitting Vulnerability (in Web Browser or Browser Plug-in like
flash, + Web Proxy)
2) Frame Injection
3) Some tricks to make it working

The goal was to have control over a browsing session among different
domains, extending control and interaction.

More info are  in the last Chapter of our Subverting Ajax Paper
(Autoinjecting Cross Domain Scripting):
http://events.ccc.de/congress/2006/Fahrplan/events/1602.en.html

At 23C3, we also had a nice conversation with Dan Kaminsky about the IE 6
vulnerability reported by Amit Klein, which was exploited to leverage the
Request Splitting. Indeed Amit Klein did a great job and he's a pioneer in
this kind of research.

Giorgio Fedon, Stefano Di Paola

> Amit Klein found the  same vector that I used here for client-side
backdoors in May 2006 (still
> not patched?! *shrieks in horror*), but for cache poisoning:
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