TippingPoint Zero Day Initiative

Microsoft Office Excel Conditional Expression Ptg Type Confusion Vulnerability

ZDI-11-280: October 13th, 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 11597. For further product information on the TippingPoint IPS:

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Microsoft Office Excel. 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 how the application parses expressions used for determining formatting requirements. Due to the application not handling certain components of the expression correctly, the application will treat one of the structures as a different type and consequently treat one of its arguments as a pointer. This pointer is used to fetch a virtual method table and can be used 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

    2011-06-01 - Vulnerability reported to vendor
    2011-10-13 - Coordinated public release of advisory


This vulnerability was discovered by: