TippingPoint Zero Day Initiative

Microsoft Internet Explorer CSS Race Condition Code Execution Vulnerability

ZDI-09-087: December 8th, 2009


Affected Vendors

Affected Products

TippingPoint™ IPS Customer Protection

TippingPoint IPS customers are protected against this vulnerability by Digital Vaccine protection filter ID 9315. For further product information on the TippingPoint IPS:

Vulnerability Details

This vulnerability allows remote attackers to potentially 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 during a race condition while repetitively clicking between two elements at a fast rate. When clicking back and forth between these two elements a corruption occurs resulting in a call to a dangling pointer which can be further leveraged into code execution via a heap spray. Exploitation of this vulnerability will lead to remote system compromise under the credentials of the currently logged in user.

Vendor Response

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

Disclosure Timeline

    2009-07-21 - Vulnerability reported to vendor
    2009-12-08 - Coordinated public release of advisory


This vulnerability was discovered by: