Additional technical information is available to describe the Microsoft Word arbitrary code execution vulnerability.
Microsoft Word contains a vulnerability that can allow an unauthenticated, remote attacker to execute arbitrary code on an affected system.
The vulnerability exists because Word does not properly handle malformed documents. An unauthenticated, remote attacker can exploit this vulnerability by convincing a user to open a malicious Word document. If the user opens 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 that correct it.
The following Microsoft products are affected:
Word 2002 SP3 and prior
Word 2003 SP3 and prior
Office for Mac 2004
Office for Mac 2008
Open XML File Format Converter for Mac
Office Word Viewer 2003 SP3 and prior
To exploit this vulnerability, an attacker must convince a user to open a malicious document. The attacker may deliver the file to the user through a website or as an attachment to an e-mail message. The attacker cannot force the user to view the file and will likely employ social engineering techniques in an attempt to convince the user to it. If the user opens the file, the attacker could execute arbitrary code with the privileges of the user.
Systems that restrict user privileges, or those with built-in user privilege separation features such as Windows Vista, may be at less risk in the event of an exploit because any code execution would occur with limited privileges. However, if the user holds elevated privileges, the attacker could execute code that results in a complete system compromise.
Microsoft has corrected this vulnerability by improving how Word handles malformed files.
Microsoft has released a security bulletin at the following link: MS09-068
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the privileges of the user. If that user holds elevated privileges, the attacker could execute code resulting in a complete system compromise.
The vulnerability exists when Microsoft Word processes File Information Block (FIB) structures in Word documents. An unauthenticated, remote attacker could exploit this vulnerability by crafting a Word document that contains a malicious FIB structure and convincing a user to open it. Processing the crafted document could cause a stack-based buffer overflow, which the attacker could leverage to execute arbitrary code with the privileges of the user.
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.
Administrators are advised to use an unprivileged account for routine activities.
Administrators are advised to implement an intrusion prevention system (IPS) or intrusion detection system (IDS) to help detect and prevent attacks that attempt to exploit this vulnerability.
Users may consider applying the Microsoft Office Isolated Conversion Environment (MOICE) to safely open Word files from suspicious or unrecognized sources on systems that are running Microsoft Office 2003 or Office 2007.
Administrators should consider disabling preview directory browsing modes. In some cases, this preview mode may process files in ways similar to opening the file, and may trigger an exploit through a malicious file in a directory or file share.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
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.
Cisco Systems Cisco Intrusion Prevention System (IPS) 6.0
Version 1, November 10, 2009, 2:02 PM: Microsoft Word contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on an affected system. Updates are available.
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