TippingPoint Zero Day Initiative

Microsoft Internet Explorer Stylesheet Array Removal Remote Code Execution Vulnerability

ZDI-10-102: June 8th, 2010


CVSS Score

Affected Vendors

Affected Products

TippingPoint™ IPS Customer Protection

TippingPoint IPS customers are protected against this vulnerability by Digital Vaccine protection filter ID 9735. For further product information on the TippingPoint IPS:

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Microsoft Internet Explorer. User interaction is required in that a target must visit a malicious page.

The specific flaw exists within IE's support for the CStyleSheet object. When a style sheet array is created it contains a reference to it's root container. If the stylesheet was created as part of an element not in a markup the root container can be freed when that element is destroyed. When the application attempts to use the stylesheet after this, an invalid pointer is utilized. This can be leveraged by attackers to execute arbitrary code under the context of the user running the browser.

Vendor Response

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

Disclosure Timeline

    2010-03-26 - Vulnerability reported to vendor
    2010-06-08 - Coordinated public release of advisory


This vulnerability was discovered by:
    Peter Vreugdenhil (http://twitter.com/WTFuzz)