TippingPoint Zero Day Initiative

Microsoft Internet Explorer 9 STYLE Object Parsing Remote Code Execution Vulnerability

ZDI-11-248: August 9th, 2011


CVSS Score

Affected Vendors

Affected Products

TippingPoint™ IPS Customer Protection

TippingPoint IPS customers are protected against this vulnerability by Digital Vaccine protection filter ID 11456. 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 to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the part of the application that is responsible for handling STYLE elements. By creating a STYLE element with an invalid behavior, an attacker can force an object of invalid type to be called, resulting in corruption of heap memory. This can be leveraged by an attacker to achieve code execution under the context of the application.

Vendor Response

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

Disclosure Timeline

    2011-05-25 - Vulnerability reported to vendor
    2011-08-09 - Coordinated public release of advisory


This vulnerability was discovered by:
    Stephen Fewer of Harmony Security (www.harmonysecurity.com)