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Microsoft Office fails to properly parse malformed strings

Vulnerability Note VU#234900

Original Release Date: 2006-10-11 | Last Revised: 2006-11-17

Overview

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

Description

Microsoft Office contains a vulnerability that could be exploited when parsing specially crafted strings. 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 Mac OS X.

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.

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.

Vendor Information

234900
 
Affected   Unknown   Unaffected

Microsoft Corporation

Updated:  October 11, 2006

Status

  Vulnerable

Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

Refer to Microsoft Security Bulletin MS06-062.

If you have feedback, comments, or additional information about this vulnerability, please send us email.


CVSS Metrics

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A

References

Acknowledgements

This vulnerability was reported in Microsoft Security Bulletin MS06-062 . Microsoft credits Dejun Meng of Fortinet Inc. for reporting this issue.

This document was written by Chris Taschner.

Other Information

CVE IDs: CVE-2006-3434
Severity Metric: 19.24
Date Public: 2006-10-10
Date First Published: 2006-10-11
Date Last Updated: 2006-11-17 20:06 UTC
Document Revision: 7

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