ZDI-06-027: Microsoft Internet Explorer CSS Class Ordering
                       Memory Corruption Vulnerability
http://www.zerodayinitiative.com/advisories/ZDI-06-027.html 
August  8, 2006

-- CVE ID:
CVE-2006-3450

-- Affected Vendor:
Microsoft

-- Affected Products:
Internet Explorer 6 All Versions
Internet Explorer 5 SP4

-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability since August  8, 2006 by Digital Vaccine protection
filter ID 4605. 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 vulnerability exists due to improper handling of CSS class
values. Accessing a specially crafted CSS element via
document.getElementByID causes a memory corruption eventually leading
to code execution.

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

http://www.microsoft.com/technet/security/bulletin/MS06-042.mspx 

-- Disclosure Timeline:
2006.06.14 - Vulnerability reported to vendor
2006.08.08 - Digital Vaccine released to TippingPoint customers
2006.08.08 - Coordinated public release of advisory

-- Credit:
This vulnerability was discovered by Sam Thomas.

-- 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.