Microsoft Office Web Components Remote Memory Corruption Vulnerability
2009.July.13

Fortinet's FortiGuard Global Security Research Team Discovers Memory Corruption Vulnerability in Microsoft Office Web Components.

Summary:
========
A memory corruption vulnerability exists in the ActiveX Controls of Microsoft Office Web Components which allows a remote attacker to compromise a system through a malicious site.

Impact:
=======
Remote Code Execution.

Risk:
=====
Critical

Affected Software:
==================
For a list of operating system and product versions affected, please see the Microsoft Security Advisory reference below.

Additional Information:
=======================
A remote attacker could craft a malicious HTML document which exploits the Internet Explorer. The vulnerability lies in the default ActiveX Control installed by the Microsoft Office. A crafted object may be created and passed to a method of this control that will cause memory corruption in the Internet Explorer. After the corruption has occured, a few specific actions will cause Internet Explorer to cause remote code execution through a call instruction.

Solutions:
==========
Use the workaround solution provided by Microsoft (973472).
The FortiGuard Global Security Research Team released a signature "MS.Office.Web.Components.Memory.Corruption", which covers this specific vulnerability.

Fortinet customers who subscribe to Fortinet's intrusion prevention (IPS) service should be protected against this remote code execution vulnerability. Fortinet's IPS service is one component of FortiGuard Subscription Services, which also offer comprehensive solutions such as antivirus, Web content filtering and antispam capabilities. These services enable protection against threats on both application and network layers. FortiGuard Services are continuously updated by the FortiGuard Global Security Research Team, which enables Fortinet to deliver a combination of multi-layered security intelligence and true zero-day protection from new and emerging threats. These updates are delivered to all FortiGate, FortiMail and FortiClient products. Fortinet strictly follows responsible disclosure guidelines to ensure optimum protection during a threat's lifecycle.

References:
===========
FortiGuard Advisory: http://www.fortiguardcenter.com/advisory/FGA-2009-27.html
Microsoft Security Advisory: http://www.microsoft.com/technet/security/advisory/973472.mspx
CVE ID: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-1136

Acknowledgement:
================
Haifei Li of Fortinet's FortiGuard Global Security Research Team


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