Additional technical information that describes the Microsoft Office Excel ActiveX Data Object processing memory corruption vulnerability is available.
Description
Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code.
The vulnerability is due to errors in processing malformed ActiveX Data Objects in Microsoft Excel documents. An unauthenticated, remote attacker could exploit this 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 Excel 2007 SP2 and prior
Office 2004 for Mac
Office 2008 for Mac
Open XML File Format Converter for Mac
Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2 and prior
IntelliShield Analysis
An attacker cannot directly exploit this vulnerability and instead must rely on user interaction to trigger an exploit. The attacker must convince the user to view a malicious document in the affected application. An attacker may provide documents to users as e-mail attachments or by providing links in e-mail or instant messages to a file posted on a website.
If the attacker downloads and views the file, the document could execute arbitrary code on the system with the privileges of the user. If the user holds elevated privileges, the attacker could install malicious software or create new user accounts, allowing the attacker to completely compromise the system.
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 the vulnerability to execute arbitrary code with the privileges of the user. If the user holds Administrator privileges, the attacker could execute code that could result in a complete system compromise.
Technical Information
The vulnerability is due to insufficient validation of DBQueryExt ActiveX Data Object (ADO) records used by Microsoft Excel. The record specifies the beginning of a collection of records for external data connections made by Microsoft Excel. The application may reference a memory pointer that contains user data, potentially leading to code execution.
An unauthenticated, remote attacker could exploit the vulnerability by convincing a user to open a malicious Microsoft Excel document that contains crafted DBQueryExt records. When Excel processes the document, the application could access a memory pointer that contains data from the attacker's document. A successful exploit could allow the attacker to access user-space memory and execute arbitrary code on the 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, 2:42 PM: Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code. Updates are available.
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