The CVSS score for this alert has been modified to reflect a higher potential for exploitation. Additional information about the malware that exploits the vulnerability is available.
Description
Microsoft Office contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code.
The vulnerability is due to improper boundary restrictions when processing Office documents. An unauthenticated, remote attacker could exploit the vulnerability by convincing the user to view a malicious document. If successful, the attacker could execute arbitrary code with the privileges of the user.
A functional exploit that is a part of the Metasploit framework is publicly available.
Microsoft has confirmed the vulnerability in a security bulletin and released software updates.
Warning Indicators
The following Microsoft products are affected:
Office XP SP3 and prior
Office 2003 SP3 and prior
Office 2007 SP2 and prior
Office 2010 (32-bit editions)
Office 2010 (64-bit editions)
Office 2004 for Mac
Office 2008 for Mac
Office for Mac 2011
Open XML File Format Converter for Mac
IntelliShield Analysis
Reports suggest that this vulnerability is being exploited in the wild using the TROJ_ARTIEF.AZ class of trojans. This malware is circulated through spam e-mail messages that contain a .doc file as an attachment. Further information about the malware that exploits the vulnerability is available in IntelliShield Alert 22988.
To exploit the vulnerability, the attacker must convince a user to open a malicious document within the vulnerable application. The attacker may provide documents directly to the user as an attachment to an e-mail message or by convincing a user to follow a link that directs the user to a file hosted on a remote file share or website. When viewed, the document could trigger the vulnerability and execute arbitrary code on the system with the privileges of the user.
The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the November 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 November 2010
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS10-087
Impact
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code on a targeted system with the privileges of the user. If that user holds elevated privileges, the attacker could completely compromise the targeted system.
Technical Information
The vulnerability is due to improper boundary restrictions while processing specific control word embedded in Rich Text Format (RTF) documents by the affected software. The affected software copies property string values associated with the control word to an insufficiently-large buffer without proper validation, which could trigger a buffer overflow.
An unauthenticated, remote attacker could exploit the vulnerability by convincing a targeted user to view a malicious document that is crafted with overly large control word property string values. When processed, the values could trigger a stack-based buffer overflow condition that corrupts memory. An attacker could use the memory corruption to execute arbitrary code with the privileges of the user.
Safeguards
Administrators are advised to apply the appropriate software updates.
Users are advised to read e-mail in plain text.
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 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 are advised to monitor critical systems.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
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 3, January 3, 2011, 8:37 AM: Proof-of-concept code that exploits the Microsoft Office Rich Text Format content processing buffer overflow vulnerability is publicly available.
Version 2, November 18, 2010, 10:20 AM: Additional technical information that describes the Microsoft Office Rich Text Format content processing buffer overflow vulnerability is publicly available.
Version 1, November 9, 2010, 1:27 PM: Microsoft Office contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on the system with the privileges of a targeted user. Updates are available.
The security vulnerability applies to the following combinations of products.
Primary Products:
Microsoft, Inc.
Office
2003 Base, SP1, SP2, SP3 | 2007 Base, SP1, SP2 | 2010 Base | XP (2002) Base, SP1, SP2, SP3
Microsoft, Inc.
Office for Mac
2004 Base | 2008 Base | 2011 Base
Microsoft, Inc.
Open XML File Format Converter for Mac
1.0 .0, .1, .2
Associated Products:
N/A
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