VUPEN Security Research - Microsoft Internet Explorer CSS @import Memory
Corruption (Pwn2Own 2014)

Website : http://www.vupen.com

Twitter : http://twitter.com/vupen


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

"Microsoft Internet Explorer is a web browser developed by Microsoft and
included as part of the Microsoft Windows line of operating systems with
more than 60% of the worldwide usage share of web browsers." (Wikipedia)


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

VUPEN Vulnerability Research Team discovered a critical vulnerability
in Microsoft Internet Explorer.

The vulnerability is caused by a use-after-free vulnerability when
manipulating CSS @import statements through "addImport()" or
"removeImport()", which could be exploited by attackers to leak
arbitrary memory or execute arbitrary code via a malicious web page.


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

Microsoft Internet Explorer 11
Microsoft Internet Explorer 10
Microsoft Internet Explorer 9


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

Apply MS14-037 security update.


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: http://www.vupen.com/english/services/


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

https://technet.microsoft.com/library/security/ms14-037
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-1763


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

2014-01-24 - Vulnerability Discovered by VUPEN Security
2014-03-14 - Vulnerability Reported to ZDI / Microsoft During Pwn2Own 2014
2014-07-08 - Vulnerability Fixed by Microsoft
2014-07-16 - Public disclosure