Microsoft Office contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code with the privileges of the user.
The vulnerability is due to improper parsing of malformed records in Microsoft Word documents. An unauthenticated, remote attacker could exploit the vulnerability by convincing a user to view a malicious document. If successful, the attacker could execute arbitrary code with the privileges of the user.
Proof-of-concept code that exploits this vulnerability is publicly available.
Microsoft has confirmed this vulnerability in a security bulletin and released updated software.
Indicators of Compromise
The following Microsoft products are affected:
Microsoft Office Word 2002 SP3
Microsoft Office Word 2003 SP3
Microsoft Office Word 2007 SP2
Microsoft Office 2004 for Mac
Microsoft Office 2008 for Mac
Open XML File Format Converter for Mac
Microsoft Office Word Viewer
Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 2
Microsoft Works 9
The vulnerability is due to improper parsing of sprmCMajority records included in Word documents. The affected software improperly checks parameters while processing sprm groups in the sprmCMajority records.
An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to open a Word document that has a crafted sprmCMajority sprm groups value. Processing the file could result in a stack-based buffer overflow, allowing the attacker to overwrite critical exception structures. The attacker could use this buffer overflow to execute arbitrary code on the targeted system with the privileges of the user.
An attacker could exploit this vulnerability only with the participation of a system user. The attacker must convince the user to open a malicious document. The attacker could provide the document to the user as an attachment to an email message or by sending links to a document that is posted on a website via email or instant messages. When the document is viewed, the attacker could execute arbitrary code on the system under the security context of the targeted user.
Administrators are advised to apply the appropriate software updates.
Users are advised not to open email messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in email 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 are advised to apply Snort SID 19459 to help prevent attacks that attempt to exploit the vulnerability.
Administrators are advised to monitor critical systems.
Microsoft has released a security bulletin at the following link: MS10-056
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.
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM
THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.
FIXED SOFTWARE INFORMATION AND LINKS PROVIDED BY SUPPLIERS AND VENDORS ARE FOR REFERENCE ONLY. USERS SHOULD CONTACT THEIR SUPPLIER OR VENDOR FOR UPDATED SOFTWARE.
A standalone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy and may lack important information or contain factual errors. The information in this document is intended for end users of Cisco products
Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.