TippingPoint Zero Day Initiative

Microsoft Internet Explorer onreadystatechange Memory Corruption Vulnerability

ZDI-09-039: June 10th, 2009


Affected Vendors

Affected Products

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.

The specific flaw exists when repeated calls are made to getElementsByTagName() and the reordering of the elements in the document causes an object to be allocated. The use of the event "onreadystatechange" during this operation improperly frees the previously allocated resource. The combination, with repeated page rendering, leads to the exploitable memory corruption.

Vendor Response

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

Disclosure Timeline

    2009-01-26 - Vulnerability reported to vendor
    2009-06-10 - Coordinated public release of advisory


This vulnerability was discovered by:
    ling&wushi of team509