VUPEN Security Research - Mozilla Firefox "nsHTMLEditRules" Remote
Use-after-free (CVE-2012-3958 / MFSA 2012-58)

Website : http://www.vupen.com/english/research.php

Twitter : http://twitter.com/vupen


I. BACKGROUND
---------------------

Mozilla Firefox is a free and open source web browser and coordinated by
Mozilla Corporation and Mozilla Foundation. As of August 2012, Firefox
has approximately 23% of worldwide usage share of web browsers (Wikipedia)


II. DESCRIPTION
---------------------

VUPEN Vulnerability Research Team discovered a critical vulnerability
in Mozilla Firefox.

The vulnerability is caused by a use-after-free error in the
"setUserData()"
method within the "nsHTMLEditRules" class, which could allow remote
attackers execute arbitrary code via a specially crafted web page.

CVSS Score: 10 (AV:N/AC:L/Au:N/C:C/I:C/A:C)


III. AFFECTED PRODUCTS
---------------------------

Mozilla Firefox versions prior to 15
Mozilla Firefox ESR versions prior to 10.0.7
Mozilla Thunderbird versions prior to 15
Mozilla Thunderbird ESR versions prior to 10.0.7
Mozilla SeaMonkey versions prior to 2.12


IV. Binary Analysis & Exploits/PoCs
---------------------------------------

In-depth technical analysis of the vulnerability and a fully functional
exploit including DEP bypass are available through the VUPEN BAE
(Binary Analysis & Exploits) portal:

http://www.vupen.com/english/services/ba-index.php

VUPEN Binary Analysis & Exploits Service provides private exploits and
in-depth technical analysis of the most significant public vulnerabilities
based on disassembly, reverse engineering, protocol analysis, and code
audit.

The service allows governments and major corporations to evaluate risks, and
protect infrastructures and assets against new threats. The service also
allows security vendors (IPS, IDS, AntiVirus) to supplement their internal
research efforts and quickly develop both vulnerability-based and
exploit-based signatures to proactively protect their customers from attacks
and emerging threats.


V. VUPEN Threat Protection Program
-----------------------------------

Governments and major corporations which are members of the VUPEN Threat
Protection Program (TPP) have been proactively alerted about the
vulnerability
when it was discovered by VUPEN in advance of its public disclosure, and
have received a detailed attack detection guidance to protect national and
critical infrastructures against potential 0-day attacks exploiting this
vulnerability:

http://www.vupen.com/english/services/tpp-index.php


VI. SOLUTION
----------------

Upgrade to Firefox 15, Firefox ESR 10.0.7, Thunderbird 15, Thunderbird ESR
10.0.7, and SeaMonkey 2.12.


VII. CREDIT
--------------

This vulnerability was discovered by Nicolas Joly of VUPEN Security


VIII. ABOUT VUPEN Security
---------------------------

VUPEN is the leading provider of advanced vulnerability research for
defensive and offensive cyber security. VUPEN solutions enable corporations
and governments to measure and manage risks, eliminate vulnerabilities
before they can be exploited, and protect critical infrastructures and
assets against known and unknown vulnerabilities.

VUPEN has been recognized as "Company of the Year 2011 in the Vulnerability
Research Market" by Frost & Sullivan.

VUPEN solutions include:

* VUPEN Binary Analysis & Exploits Service (BAE) :
http://www.vupen.com/english/services/ba-index.php

* VUPEN Threat Protection Program (TPP) :
http://www.vupen.com/english/services/tpp-index.php


IX. REFERENCES
----------------------

http://www.mozilla.org/security/announce/2012/mfsa2012-58.html
http://www.vupen.com


X. DISCLOSURE TIMELINE
-----------------------------

2012-07-15 - Vulnerability Discovered by VUPEN and shared with customers
2012-08-28 - Public disclosure