NSFOCUS Security Advisory (SA2006-05)

Microsoft Excel SELECTION Record Memory Corruption Vulnerability 

Release Date: 2006-07-12

CVE ID: CVE-2006-1302

http://www.nsfocus.com/english/homepage/research/0605.htm

Affected systems & software
===================
Microsoft Excel 2000
Microsoft Excel 2002
Microsoft Excel 2003

Unaffected systems & software
===================


Summary
=========

NSFocus Security Team discovered a memory corruption vulnerability in Microsoft 
Excel's processing of SELECTION record, which allows remote attackers to run 
arbitrary via carefully crafted Excel files. 

Description
============

Excel does not perform sufficient check for certain field when processing 
SELECTION record. During some data copying operation the user-supplied data 
might be used for the copying, resulting in memory corruption and arbitrary 
code execution. 

Attackers can craft an Excel file with malformed SELECTION record and allure 
users to open it via instant messaging tools, e-mail or other vectors, resulting 
in arbitrary code execution with the privilege of the user. If the user is 
the administrator, then attackers might take complete control over the system. 

Workaround
=============

Do not open any Excel file from untrusted sources. 
    
Vendor Status
==============

2006.03.30  Informed the vendor
2006.04.03  Vendor confirmed the vulnerability
2006.07.11  Microsoft has released a security bulletin (MS06-037) and related 
            patches. 
            
For more details about the security bulletin, please refer to: 
http://www.microsoft.com/technet/security/bulletin/MS06-037.mspx

Additional Information
========================

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2006-1302 to this issue. This is a candidate for inclusion in the 
CVE list (http://cve.mitre.org), which standardizes names for security problems.
Candidates may change significantly before they become official CVE entries.

Acknowledgment
===============

Wen Yujie of NSFocus Security Team found the vulnerability.

DISCLAIMS
==========
THE INFORMATION PROVIDED IS RELEASED BY NSFOCUS "AS IS" WITHOUT WARRANTY
OF ANY KIND. NSFOCUS DISCLAIMS ALL WARRANTIES, EITHER EXPRESSED OR IMPLIED,
EXCEPT FOR THE WARRANTIES OF MERCHANTABILITY. IN NO EVENT SHALL NSFOCUS
BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT,
INCIDENTAL,CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES,
EVEN IF NSFOCUS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
DISTRIBUTION OR REPRODUCTION OF THE INFORMATION IS PROVIDED THAT THE
ADVISORY IS NOT MODIFIED IN ANY WAY.

Copyright 1999-2006 NSFOCUS. All Rights Reserved. Terms of use.


NSFOCUS Security Team <security@nsfocus.com>
NSFOCUS INFORMATION TECHNOLOGY CO.,LTD
(http://www.nsfocus.com)

PGP Key: http://www.nsfocus.com/homepage/research/pgpkey.asc
Key fingerprint = F8F2 F5D1 EF74 E08C 02FE 1B90 D7BF 7877 C6A6 F6DA