ZDI-07-037: Microsoft Internet Explorer Language Pack Installation
            Remote Code Execution Vulnerability
http://www.zerodayinitiative.com/advisories/ZDI-07-037.html
June 12, 2007

-- CVE ID:
CVE-2007-3027

-- Affected Vendor:
Microsoft

-- Affected Products:
Internet Explorer 6.x
Internet Explorer 7.x

-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability since February 27, 2006 by Digital Vaccine protection
filter ID 3377,4163. For further product information on the TippingPoint 
IPS:

    http://www.tippingpoint.com 

-- Vulnerability Details:
This vulnerability allows attackers to execute arbitrary code on
vulnerable installations of Microsoft Internet Explorer. User
interaction is required to exploit this vulnerability in that the
target must visit a malicious page.

The specific flaw exists in routines responsible for the on-demand
installation of Internet Explorer language packs. A race condition may
occur when a web page contains several pieces of content written in a
language not currently supported by any of the installed language
packs. In some cases, this race condition results in exploitable memory
corruption that can be leveraged to execute arbitrary code.

-- Vendor Response:
Microsoft has issued an update to correct this vulnerability. More
details can be found at:

    http://www.microsoft.com/technet/security/bulletin/ms07-033.mspx

-- Disclosure Timeline:
2006.02.27 - Digital Vaccine released to TippingPoint customers
2006.11.08 - Vulnerability reported to vendor
2007.06.12 - Coordinated public release of advisory

-- Credit:
This vulnerability was discovered by an anonymous researcher.

-- About the Zero Day Initiative (ZDI):
Established by TippingPoint, a division of 3Com, The Zero Day Initiative
(ZDI) represents a best-of-breed model for rewarding security
researchers for responsibly disclosing discovered vulnerabilities.

Researchers interested in getting paid for their security research
through the ZDI can find more information and sign-up at:

    http://www.zerodayinitiative.com

The ZDI is unique in how the acquired vulnerability information is used.
3Com does not re-sell the vulnerability details or any exploit code.
Instead, upon notifying the affected product vendor, 3Com provides its
customers with zero day protection through its intrusion prevention
technology. Explicit details regarding the specifics of the
vulnerability are not exposed to any parties until an official vendor
patch is publicly available. Furthermore, with the altruistic aim of
helping to secure a broader user base, 3Com provides this vulnerability
information confidentially to security vendors (including competitors)
who have a vulnerability protection or mitigation product.

CONFIDENTIALITY NOTICE: This e-mail message, including any attachments,
is being sent by 3Com for the sole use of the intended recipient(s) and
may contain confidential, proprietary and/or privileged information.
Any unauthorized review, use, disclosure and/or distribution by any 
recipient is prohibited.  If you are not the intended recipient, please
delete and/or destroy all copies of this message regardless of form and
any included attachments and notify 3Com immediately by contacting the
sender via reply e-mail or forwarding to 3Com at postmaster@3com.com.