http://www.microsoft.com/technet/security/advisory/932553.mspxMicrosoft Security Advisory (932553)
Vulnerability in Microsoft Office Could Allow Remote Code Execution
Published: February 2, 2007
Microsoft is investigating new public reports of very limited Microsoft Excel “zero-day” attacks using a vulnerability in Microsoft Office 2000, Microsoft Office XP, Microsoft Office 2003, and Microsoft Office 2004 for Mac
In order for this attack to be carried out, a user must first open a malicious Office file attached to an e-mail or otherwise provided to them by an attacker.
While we are currently only aware that Excel is the current attack vector, other Office applications are potentially vulnerable.
As a best practice, users should always exercise extreme caution when opening unsolicited attachments from both known and unknown sources. Microsoft has added detection to the Windows Live OneCare safety scanner for up-to-date removal of malicious software that attempts to exploit this vulnerability.
Microsoft intends to actively share information with Microsoft Security Response Alliance partners so that their detection can be up to date to detect and remove attacks.
Customers in the U.S. and Canada who believe they are affected can receive technical support from Microsoft Product Support Services at 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates.
International customers can receive support from their local Microsoft subsidiaries. There is no charge for support that is associated with security updates. For more information about how to contact Microsoft for support issues, visit the International Support Web site.
Upon completion of this investigation, Microsoft will take the appropriate action to help protect our customers. This may include providing a security update through our monthly release process or providing an out-of-cycle security update, depending on customer needs.
General Information
Overview
Purpose of Advisory: To provide customers with initial notification of the publicly disclosed vulnerability. For more information see the “Workarounds and Mitigations” and “Suggested Actions” section of the security advisory.
Advisory Status: Under Investigation.
Recommendation: Do not open or save Office files that you receive from un-trusted or that are received unexpected from trusted sources. This vulnerability could be exploited when a user opens a file.
References Identification
CVE Reference
CVE-2007-0671
This advisory discusses the following software.
Related Software
Office 2000
Office XP
Office 2003
Office 2004 for Mac
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Frequently Asked Questions
What is the scope of the advisory?
Microsoft is aware of a new vulnerability report affecting Office, which is a component of Microsoft Office. This vulnerability affects the software that is listed in the “Overview” section.
Is this a security vulnerability that requires Microsoft to issue a security update?
Microsoft is developing a security update for Office that addresses this vulnerability.
What versions of Microsoft Office are associated with this advisory?
This advisory addresses Office 2000, and Office 2004 for Mac.
What causes the vulnerability?
When a user opens a specially crafted Office file using a malformed string, it may corrupt system memory in such a way that an attacker could execute arbitrary code.
How could an attacker exploit the vulnerability?
In a Web-based attack scenario, an attacker would have to host a Web site that contains a Office file that is used to attempt to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content could contain specially crafted content that could exploit this vulnerability An attacker would have no way to force users to visit a malicious Web site. Instead, an attacker would have to persuade them to visit the Web site, typically by getting them to click a link that takes them to the attacker's site.
In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially-crafted file to the user and by persuading the user to open the file.
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Mitigating Factors for Microsoft Office Remote Code Execution Vulnerability:
The vulnerability cannot be exploited on Office 2007 or on Works 2004, 2005, or 2006.
An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. Users whose accounts are configured to have fewer user rights on the system could be less affected than users who operate with administrative user rights.
In a Web-based attack scenario, an attacker would have to host a Web site that contains a Office file that is used to attempt to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content could contain specially crafted content that could exploit this vulnerability. An attacker would have no way to force users to visit a malicious Web site. Instead, an attacker would have to persuade them to visit the Web site, typically by getting them to click a link that takes them to the attacker's site.
The vulnerability cannot be exploited automatically through e-mail. For an attack to be successful a user must open an attachment that is sent in an e-mail message.
Users who have installed and are using the Office Document Open Confirmation Tool for Office 2000 will be prompted with Open, Save, or Cancel before opening a document.
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Workarounds for Microsoft Office Remote Code Vulnerability:
Microsoft has tested the following workarounds. While these workarounds will not correct the underlying vulnerability, they help block known attack vectors. When a workaround reduces functionality, it is identified in the following section.
Do not open or save Office files that you receive from un-trusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted Office file.
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Suggested Actions
Protect Your PC
We continue to encourage customers follow our Protect Your PC guidance of enabling a firewall, getting software updates and installing ant-virus software. Customers can learn more about these steps by visiting Protect Your PC Web site.
For more information about staying safe on the Internet, customers can visit the Microsoft Security Home Page.
Customers who believe they have been attacked should contact their local FBI office or post their complaint on the Internet Fraud Complaint Center Web site. Customers outside the U.S. should contact the national law enforcement agency in their country.
All customers should apply the most recent security updates released by Microsoft to help ensure that their systems are protected from attempted exploitation. Customers who have enabled Automatic Updates will automatically receive all Windows updates. For more information about security updates, visit the Microsoft Security Web site.
We recommend that customers exercise extreme caution when they accept file transfers from both known and unknown sources. For more information about how to help protect your computer while you use MSN Messenger, visit the MSN Messenger Frequently Asked Questions Web site.
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Resources:
You can provide feedback by completing the form by visiting the following Web site.
Customers in the U.S. and Canada can receive technical support from Microsoft Product Support Services. For more information about available support options, see the Microsoft Help and Support Web site.
International customers can receive support from their local Microsoft subsidiaries. For more information about how to contact Microsoft for international support issues, visit the International Support Web site.
The Microsoft TechNet Security Web site provides additional information about security in Microsoft products.
Disclaimer:
The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
Revisions:
V1.0 (February 2, 2007): Advisory published.
