TippingPoint Zero Day Initiative

(Pwn2Own) Microsoft Internet Explorer onPropertyChange Remote Code Execution Vulnerability

ZDI-11-119: April 12th, 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 11040. For further product information on the TippingPoint IPS:

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of 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 way Internet Explorer handles onPropertyChange function calls. When the onPropertyChange event handler is set to an object's attribute collection, it fails to keep an accurate reference counter to the event object. The effect of this can be that the program frees the event object while there are still references to it. This can result in remote code execution under the content of the current user.

Vendor Response

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

Disclosure Timeline

    2011-03-09 - Vulnerability reported to vendor
    2011-04-12 - Coordinated public release of advisory


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