Vulnerability Note VU#176556

Microsoft Office fails to properly parse malformed records

Overview

A vulnerability in the way Microsoft Office parses files containing malformed records may lead to execution of arbitrary code.

I. Description

Microsoft Office contains a vulnerability that could be exploited when Office attempts to parse specially crafted records. According to Microsoft Security Bulletin MS06-062:

When Office opens a specially crafted file and parses a malformed string, it may corrupt system memory in such a way that an attacker could execute arbitrary code.

This vulnerability affects Microsoft Office for both Microsoft Windows and Apple Macintosh.

II. Impact

A remote, unauthenticated attacker may be able to execute arbitrary code with the privileges of the affected user or cause a denial-of-service condition.

III. Solution

Update

Microsoft has released an update to address this issue. See Microsoft Security Bulletin MS06-062 for more details.

Do not open untrusted Microsoft Office documents

Do not open unfamiliar or unexpected Microsoft Office documents, particularly those hosted on web sites or delivered as email attachments. Please see Cyber Security Tip ST04-010.

Disable automatic opening of Microsoft Office documents

By default, Microsoft Office 97 and Microsoft Office 2000 will configure Internet Explorer to automatically open Microsoft Office documents. This feature can be disabled by using the Office Document Open Confirmation Tool. Mozilla Firefox users should disable automatic opening of files, as specified in the Securing Your Web Browser document.

Do not rely on file name extension filtering

In most cases, Windows will call a Microsoft Office application to open a document, even if the document has an unknown file extension. Filtering for common extensions (e.g., .ppt, .xls, and .doc) will not detect all Microsoft Office documents. Additionally, a Microsoft Office file with no file extension will also open with a Microsoft Office application.

Systems Affected

Vendor	Status	Date Updated
Microsoft Corporation	Vulnerable	10-Oct-2006

References

http://www.microsoft.com/technet/security/bulletin/ms06-062.mspx

Credit

This vulnerability was reported in Microsoft Security Bulletin MS06-062. Microsoft credits Sowhat of Nevis Labs for reporting this issue.

This document was written by Chris Taschner.

Other Information

Date Public	10/10/2006
Date First Published	10/11/2006 10:40:23 AM
Date Last Updated	11/06/2006
CERT Advisory
CVE Name	CVE-2006-3864
US-CERT Technical Alerts
Metric	19.24
Document Revision	9

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Produced 2006 by US-CERT, a government organization
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