VUPEN Security Research - Mozilla Firefox "BumpChunk" Object Processing
Use-after-free (Pwn2Own)

Website : https://www.vupen.com

Twitter : https://twitter.com/vupen


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

"Mozilla Firefox is a free and open-source web browser developed for
Windows, OS X, and Linux, with a mobile version for Android, by the
Mozilla Foundation and its subsidiary, the Mozilla Corporation.
As of February 2014, Firefox has between 12% and 22% of worldwide
usage, according to different sources." (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 JS engine
when processing "BumpChunk" objects while the browser is under a memory
pressure, which could be exploited to leak arbitrary memory and/or
achieve code execution via a malicious web page.


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

Mozilla Firefox versions prior to 28
Mozilla Firefox ESR versions prior to 24.4
Mozilla Thunderbird versions prior to 24.4
Mozilla Seamonkey versions prior to 2.25


IV. SOLUTION
----------------

Upgrade to Firefox v28, Firefox ESR v24.4, Thunderbird v24.4 and
Seamonkey v2.25.


V. CREDIT
--------------

This vulnerability was discovered by VUPEN Security.


VI. ABOUT VUPEN Security
---------------------------

VUPEN is the leading provider of defensive and offensive cyber security
intelligence and advanced zero-day research. All VUPEN's vulnerability
intelligence results exclusively from its internal and in-house R&D
efforts conducted by its team of world-class researchers.

VUPEN Solutions: https://www.vupen.com/english/services/


VII. REFERENCES
----------------------

https://www.mozilla.org/security/announce/2014/mfsa2014-30.html


VIII. DISCLOSURE TIMELINE
-----------------------------

2014-01-19 - Vulnerability Discovered by VUPEN Security
2014-03-12 - Vulnerability Reported to Mozilla/ZDI During Pwn2Own 2014
2014-03-18 - Vulnerability Fixed by Mozilla
2014-03-26 - Public disclosure