Additional technical information is available to describe the Microsoft Office Excel object processing memory corruption vulnerability.
Description
Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code.
The vulnerability is due to errors that may occur when Excel processes malformed objects.
An unauthenticated, remote attacker could exploit the vulnerability by convincing a user to view a malicious Excel file. If the user views the file, the attacker could execute arbitrary code with the privileges of the user.
Microsoft has confirmed this vulnerability in a security bulletin and released software updates.
Warning Indicators
The following Microsoft products are affected:
Office Excel 2002 SP3 and prior
Office 2004 for Mac
Office 2008 for Mac
Open XML File Format Converter for Mac
IntelliShield Analysis
An attacker cannot directly exploit the vulnerability, and must rely on user interaction to accomplish an exploit. The attacker must convince the user to accept and open a malicious document in Excel. Attackers may provide documents to users as attachments to e-mail messages or by providing links in e-mail messages or instant messages that direct the user to a malicious document.
If the user downloads and opens the document, the attacker could trigger the execution of arbitrary code on the system. If the user holds elevated privileges or runs applications as Administrator, the attacker could execute code that results in a complete system compromise.
The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the June 2010 security bulletin release. This Cisco bulletin, which assists administrators in identifying or mitigating these vulnerabilities using Cisco devices, is available at the following link: Cisco Applied Mitigation Bulletin: Microsoft Security Bulletin Release for June 2010
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS10-038
Impact
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the privileges of the user. If the user holds elevated privileges, the attacker could gain complete control over the system.
Technical Information
The vulnerability is due to insufficient boundary restrictions on EDG and Publisher records that are used by Microsoft Excel.
An unauthenticated, remote attacker could exploit the vulnerability by convincing a user to open a malicious Excel document that contains malformed EDG and Publisher records. Processing this document could cause a heap-based overflow, which may corrupt memory. The attacker could leverage the memory corruption to execute arbitrary code on the targeted system.
Safeguards
Administrators are advised to apply the appropriate updates.
Users are advised not to open e-mail messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in e-mail messages are safe, they are advised not to open them.
Users are advised to run applications with the least necessary privileges.
Users may consider applying the Microsoft Office Isolated Conversion Environment (MOICE) to safely open Word, Excel, and PowerPoint files from suspicious or unrecognized sources on systems that are running Microsoft Office 2003 or Office 2007.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
Administrators are advised to monitor critical systems.
Patches/Software
Microsoft customers can obtain updates directly by using the links in the security bulletin. These updates are also distributed by Windows automatic update features and available on the Windows Update website. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
Signatures
Cisco Systems Cisco Intrusion Prevention System (IPS) 6.0
Version 1, June 8, 2010, 2:32 PM: Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code. Updates are available.
The security vulnerability applies to the following combinations of products.
Primary Products:
Microsoft, Inc.
Excel
2002 (XP) Base, SP1, SP2, SP3
Microsoft, Inc.
Office for Mac
2004 Base | 2008 Base
Microsoft, Inc.
Open XML File Format Converter for Mac
1.0 .0, .1, .2
Associated Products:
Microsoft, Inc.
Office
XP (2002) Base, SP1, SP2, SP3
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