NSFOCUS Security Advisory (SA2006-06)

Microsoft Excel COLINFO Record Buffer Overflow Vulnerability

Release Date: 2006-07-12

CVE ID: CVE-2006-1304

http://www.nsfocus.com/english/homepage/research/0606.htm

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

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


Summary
=========

NSFocus Security Team discovered a buffer overflow vulnerability in Microsoft Excel's
processing of COLINFO 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 
COLINFO record, which might cause a buffer overflow vulnerability in data filling
operation. Attackers can run arbitrary via carefully craft data.

Attackers can craft an Excel file with malformed COLINFO 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-2006-1304 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.

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==========
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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