SecurityvulnsSECURITYVULNS:DOC:22770Microsoft Security Bulletin MS09-067 - Important Vulnerabilities in Microsoft Office Excel Could Allow Remote Code Execution (972652)
Microsoft Security Bulletin MS09-067 - Important
Vulnerabilities in Microsoft Office Excel Could Allow Remote Code Execution (972652)
Published: November 10, 2009
Version: 1.0
General Information
Executive Summary
This security update resolves several privately reported vulnerabilities in Microsoft Office Excel. The vulnerabilities could allow remote code execution if a user opens a specially crafted Excel file. An attacker who successfully exploited any of these vulnerabilities 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 impacted than users who operate with administrative user rights.
This security update is rated Important for all supported editions of Microsoft Office Excel 2002, Microsoft Office Excel 2003, Microsoft Office Excel 2007, Microsoft Office 2004 for Mac, and Microsoft Office 2008 for Mac; Open XML File Format Converter for Mac; and all supported versions of Microsoft Office Excel Viewer and Microsoft Office Compatibility Pack.
The update addresses the vulnerabilities by modifying the way that Excel opens and parses Excel files, and by modifying the way that Excel handles malformed records. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.
Recommendation. Microsoft recommends that customers apply the update at the earliest opportunity.
Known Issues. Microsoft Knowledge Base Article 972652 documents the currently known issues that customers may experience when installing this security update. The article also documents recommended solutions for these issues. When currently known issues and recommended solutions pertain only to specific releases of this software, this article provides links to further articles.
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Affected and Non-Affected Software
The following software have been tested to determine which versions or editions are affected. Other versions or editions are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, visit Microsoft Support Lifecycle.
Affected Software
Office Suite and Other Software Component Maximum Security Impact Aggregate Severity Rating Bulletins Replaced by this Update
Microsoft Office Suites and Components
Microsoft Office XP Service Pack 3
Microsoft Office Excel 2002 Service Pack 3
(KB973471)
Remote Code Execution
Important
MS09-021
Microsoft Office 2003 Service Pack 3
Microsoft Office Excel 2003 Service Pack 3
(KB973475)
Remote Code Execution
Important
MS09-021
2007 Microsoft Office System Service Pack 1 and 2007 Microsoft Office System Service Pack 2
Microsoft Office Excel 2007 Service Pack 1 and Microsoft Office Excel 2007 Service Pack 2*
(KB973593)
Remote Code Execution
Important
MS09-021
Microsoft Office for Mac
Microsoft Office 2004 for Mac
(KB976830)
Not applicable
Remote Code Execution
Important
MS09-021
Microsoft Office 2008 for Mac
(KB976828)
Not applicable
Remote Code Execution
Important
MS09-021
Open XML File Format Converter for Mac
(KB976831)
Not applicable
Remote Code Execution
Important
MS09-021
Other Office Software
Microsoft Office Excel Viewer 2003 Service Pack 3
(KB973484)
Not applicable
Remote Code Execution
Important
MS09-021
Microsoft Office Excel Viewer Service Pack 1 and Microsoft Office Excel Viewer Service Pack 2
(KB973707)
Not applicable
Remote Code Execution
Important
MS09-021
Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 1 and Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 2
(KB973704)
Not applicable
Remote Code Execution
Important
MS09-021
*For Microsoft Office Excel 2007 Service Pack 1 and Microsoft Office Excel 2007 Service Pack 2, in addition to security update package KB973593, customers also need to install the security update for Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 1 and Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 2 (KB973704) to be protected from the vulnerabilities described in this bulletin.
Non-Affected Software
Office and Other Software
Microsoft Office Converter Pack
Works 8.5
Works 9
Microsoft Office SharePoint Server 2003 Service Pack 3
Microsoft Office SharePoint Server 2007 Service Pack 1 and Microsoft Office SharePoint Server 2007 Service Pack 2 (32-bit editions)
Microsoft Office SharePoint Server 2007 Service Pack 1 and Microsoft Office SharePoint Server 2007 Service Pack 2 (64-bit editions)
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Frequently Asked Questions (FAQ) Related to This Security Update
Where are the file information details?
Refer to the reference tables in the Security Update Deployment section for the location of the file information details.
What are the known issues that customers may experience when installing this security update?
Microsoft Knowledge Base Article 972652 documents the currently known issues that customers may experience when they install this security update. The article also documents recommended solutions for these issues.
Does this update contain any non-security related changes to functionality?
Yes. After this security update is installed, if a user opens a specially crafted Excel file, Excel may exit unexpectedly but the vulnerabilities addressed in this update will not be exploitable.
Why does this update address several reported security vulnerabilities?
This update contains support for several vulnerabilities because the modifications that are required to address these issues are located in related files. Instead of having to install several updates that are almost the same, customers need to install this update only.
What components of the Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats are updated by this bulletin?
The update included with this security bulletin applies only to the specific component within the Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats that is affected. For example, in an Excel bulletin, only the Excel compatibility pack component files are included in the update packages and not Word or PowerPoint compatibility pack component files. Word compatibility pack component files are updated in a Word bulletin and PowerPoint compatibility pack component files are updated in a PowerPoint bulletin.
What is the Microsoft Office Excel Viewer?
The Microsoft Office Excel Viewer is a replacement for all previous Excel Viewer versions, including Excel Viewer 97 and Excel Viewer 2003. With Excel Viewer, you can open, view, and print Excel workbooks, even if you don't have Excel installed. You can also copy data from Excel Viewer to another program. However, you cannot edit data, save a workbook, or create a new workbook.
MS09-068 also describes vulnerabilities in Microsoft Office 2004 for Mac, Microsoft Office 2008 for Mac, and Open XML File Format Converter for Mac. How does MS09-068 relate to this bulletin (MS09-067)?
The security update packages in this bulletin, MS09-067, for Microsoft Office 2004 for Mac (KB976830), Microsoft Office 2008 for Mac (KB976828), and Open XML File Format Converter for Mac (KB976831) also address the vulnerabilities described in MS09-068. Users with Microsoft Office 2004 for Mac, Microsoft Office 2008 for Mac, or Open XML File Format Converter for Mac installed will only need to install these security update packages once.
The Office component discussed in this article is part of the Office Suite that I have installed on my system; however, I did not choose to install this specific component. Will I be offered this update?
Yes, if the version of the Office Suite installed on your system shipped with the component discussed in this bulletin, the system will be offered updates for it whether the component is installed or not. The detection logic used to scan for affected systems is designed to check for updates for all components that shipped with the particular Office Suite and offer the updates to a system. Users who choose not to apply an update for a component that is not installed, but is included in their version of the Office Suite, will not increase the security risk of that system. On the other hand, users who do choose to install the update will not have a negative impact on the security or performance of a system.
Does the offer to update a non-vulnerable version of Microsoft Office constitute an issue in the Microsoft update mechanism?
No, the update mechanism is functioning correctly in that it detects a lower version of the files on the system than in the update package and thus, offers the update.
Why is this update only Important for all affected versions of Excel?
Microsoft Office Excel 2002 and later versions have a built-in feature that prompts a user to Open, Save, or Cancel before opening a document. This mitigating factor reduces the vulnerability from Critical to Important because the vulnerability requires more than a single user action to complete the exploit.
I am using an older release of the software discussed in this security bulletin. What should I do?
The affected software listed in this bulletin have been tested to determine which releases are affected. Other releases are past their support life cycle. For more information about the product lifecycle, visit the Microsoft Support Lifecycle Web site.
It should be a priority for customers who have older releases of the software to migrate to supported releases to prevent potential exposure to vulnerabilities. To determine the support lifecycle for your software release, see Select a Product for Lifecycle Information. For more information about service packs for these software releases, see Lifecycle Supported Service Packs.
Customers who require custom support for older software must contact their Microsoft account team representative, their Technical Account Manager, or the appropriate Microsoft partner representative for custom support options. Customers without an Alliance, Premier, or Authorized Contract can contact their local Microsoft sales office. For contact information, visit the Microsoft Worldwide Information Web site, select the country in the Contact Information list, and then click Go to see a list of telephone numbers. When you call, ask to speak with the local Premier Support sales manager. For more information, see the Microsoft Support Lifecycle Policy FAQ.
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Vulnerability Information
Severity Ratings and Vulnerability Identifiers
The following severity ratings assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin's release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the November bulletin summary. For more information, see Microsoft Exploitability Index.
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Excel Cache Memory Corruption Vulnerability - CVE-2009-3127 Excel SxView Memory Corruption Vulnerability - CVE-2009-3128 Excel Featheader Record Memory Corruption Vulnerability - CVE-2009-3129 Excel Document Parsing Heap Overflow Vulnerability - CVE-2009-3130 Excel Formula Parsing Memory Corruption Vulnerability - CVE-2009-3131 Excel Index Parsing Vulnerability - CVE-2009-3132 Excel Document Parsing Memory Corruption Vulnerability - CVE-2009-3133 Excel Field Sanitization Vulnerability - CVE-2009-3134 Aggregate Severity Rating
Microsoft Office Suites and Components
Microsoft Office Excel 2002 Service Pack 3
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Microsoft Office Excel 2003 Service Pack 3
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Microsoft Office Excel 2007 Service Pack 1 and Microsoft Office Excel 2007 Service Pack 2
Not applicable
Not applicable
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Microsoft Office for Mac
Microsoft Office 2004 for Mac
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Microsoft Office 2008 for Mac
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Open XML File Format Converter for Mac
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Important
Other Office Software
Microsoft Office Excel Viewer 2003 Service Pack 3
Important
Remote Code Execution
Important
Remote Code Execution
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Microsoft Office Excel Viewer Service Pack 1 and Microsoft Office Excel Viewer Service Pack 2
Not applicable
Not applicable
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 1 and Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 2
Not applicable
Not applicable
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
Remote Code Execution
Not applicable
Important
Remote Code Execution
Important
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Excel Cache Memory Corruption Vulnerability - CVE-2009-3127
A remote code execution vulnerability exists in the way that Microsoft Office Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2009-3127.
Mitigating Factors for Excel Cache Memory Corruption Vulnerability - CVE-2009-3127
Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:
•
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.
•
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 impacted than users who operate with administrative user rights.
•
Users of Office XP and later editions of Office will be prompted with Open, Save, or Cancel before opening a document.
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Workarounds for Excel Cache Memory Corruption Vulnerability - CVE-2009-3127
Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:
•
Use Microsoft Office File Block policy to block the opening of Office 2003 and earlier documents from unknown or untrusted sources and locations
The following registry scripts can be used to set the File Block policy.
Note Modifying the Registry incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from incorrect modification of the Registry can be solved. Modify the Registry at your own risk.
•
For Office 2003
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001
Note In order to use 'FileOpenBlock' with Office 2003, all of the latest Office 2003 security updates must be applied.
Impact of workaround. Users who have configured the File Block policy and have not configured a special “exempt directory” as discussed in Microsoft Knowledge Base Article 922848 will be unable to open Office 2003 files or earlier versions in Office 2003 or 2007 Microsoft Office System.
How to undo the workaround:
•
For Office 2003
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
•
Use the Microsoft Office Isolated Conversion Environment (MOICE) when opening files from unknown or untrusted sources
The Microsoft Office Isolated Conversion Environment (MOICE) will protect Office 2003 installations by more securely opening Word, Excel, and PowerPoint binary format files.
To install MOICE, you must have Office 2003 or 2007 Office system installed.
To install MOICE, you must have the Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats. The compatibility pack is available as a free download from the Microsoft Download Center:
Download the FileFormatConverters.exe package now
MOICE requires all updates that are recommended for all Office programs. Visit Microsoft Update to install all recommended updates:
http://update.microsoft.com/microsoftupdate/v6/default.aspx?ln=en-us
To enable MOICE, change the registered handler for the .xls, .xlt, and .xla file formats. The following table describes the command to enable or to disable MOICE for the .xls, .xlt, and .xla file formats:
Command to enable MOICE to be the registered handler Command to disable MOICE as the registered handler
ASSOC .XLS=oice.excel.sheet
ASSOC .xls=Excel.Sheet.8
ASSOC .XLT=oice.excel.template
ASSOC .xlt=Excel.Template
ASSOC .XLA=oice.excel.addin
ASSOC .xla=Excel.Addin
Note On Windows Vista and Windows Server 2008, the commands above will need to be run from an elevated command prompt.
For more information on MOICE, see Microsoft Knowledge Base Article 935865.
Impact of workaround. Office 2003 and earlier formatted documents that are converted to the 2007 Microsoft Office System Open XML format by MOICE will not retain macro functionality. Additionally, documents with passwords or that are protected with Digital Rights Management cannot be converted.
•
Do not open Excel files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for Excel Cache Memory Corruption Vulnerability - CVE-2009-3127
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system remotely. An attacker could then install programs or view, change, or delete data; or create new accounts with full user rights.
What causes the vulnerability?
The vulnerability exists in the way that Microsoft Office Excel parses the Excel spreadsheet file format when opening a specially crafted Excel spreadsheet.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel spreadsheet with an affected version of Microsoft Office Excel.
In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially crafted Excel file to the user and by convincing the user to open the file.
In a Web-based attack scenario, an attacker would have to host a Web site that contains an 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 specially crafted Web site. Instead, an attacker would have to convince them to visit the Web site, typically by getting them to click a link that takes them to the attacker's site, and then convince them to open the specially crafted Excel file.
What systems are primarily at risk from the vulnerability?
Systems where Microsoft Office Excel is used, including workstations and terminal servers, are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.
What does the update do?
This update addresses the vulnerability by changing the way that Microsoft Office Excel parses specially crafted Excel files.
When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.
When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Excel SxView Memory Corruption Vulnerability - CVE-2009-3128
A remote code execution vulnerability exists in the way Microsoft Office Excel handles specially crafted Excel files that include a malformed record object. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2009-3128.
Mitigating Factors for Excel SxView Memory Corruption Vulnerability - CVE-2009-3128
Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:
•
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.
•
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 impacted than users who operate with administrative user rights.
•
Users of Office XP and later editions of Office will be prompted with Open, Save, or Cancel before opening a document.
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Workarounds for Excel SxView Memory Corruption Vulnerability - CVE-2009-3128
Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:
•
Use Microsoft Office File Block policy to block the opening of Office 2003 and earlier documents from unknown or untrusted sources and locations
The following registry scripts can be used to set the File Block policy.
Note Modifying the Registry incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from incorrect modification of the Registry can be solved. Modify the Registry at your own risk.
•
For Office 2003
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001
Note In order to use 'FileOpenBlock' with Office 2003, all of the latest Office 2003 security updates must be applied.
Impact of workaround. Users who have configured the File Block policy and have not configured a special “exempt directory” as discussed in Microsoft Knowledge Base Article 922848 will be unable to open Office 2003 files or earlier versions in Office 2003 or 2007 Microsoft Office System.
How to undo the workaround:
•
For Office 2003
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
•
Use the Microsoft Office Isolated Conversion Environment (MOICE) when opening files from unknown or untrusted sources
The Microsoft Office Isolated Conversion Environment (MOICE) will protect Office 2003 installations by more securely opening Word, Excel, and PowerPoint binary format files.
To install MOICE, you must have Office 2003 or 2007 Office system installed.
To install MOICE, you must have the Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats. The compatibility pack is available as a free download from the Microsoft Download Center:
Download the FileFormatConverters.exe package now
MOICE requires all updates that are recommended for all Office programs. Visit Microsoft Update to install all recommended updates:
http://update.microsoft.com/microsoftupdate/v6/default.aspx?ln=en-us
To enable MOICE, change the registered handler for the .xls, .xlt, and .xla file formats. The following table describes the command to enable or to disable MOICE for the .xls, .xlt, and .xla file formats:
Command to enable MOICE to be the registered handler Command to disable MOICE as the registered handler
ASSOC .XLS=oice.excel.sheet
ASSOC .xls=Excel.Sheet.8
ASSOC .XLT=oice.excel.template
ASSOC .xlt=Excel.Template
ASSOC .XLA=oice.excel.addin
ASSOC .xla=Excel.Addin
Note On Windows Vista and Windows Server 2008, the commands above will need to be run from an elevated command prompt.
For more information on MOICE, see Microsoft Knowledge Base Article 935865.
Impact of workaround. Office 2003 and earlier formatted documents that are converted to the 2007 Microsoft Office System Open XML format by MOICE will not retain macro functionality. Additionally, documents with passwords or that are protected with Digital Rights Management cannot be converted.
•
Do not open Excel files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for Excel SxView Memory Corruption Vulnerability - CVE-2009-3128
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system remotely. An attacker could then install programs or view, change, or delete data; or create new accounts with full user rights.
What causes the vulnerability?
The vulnerability exists in the way that Microsoft Office Excel parses the Excel spreadsheet file format when opening a specially crafted Excel spreadsheet
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel spreadsheet with an affected version of Microsoft Office Excel.
In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially crafted Excel file to the user and by convincing the user to open the file.
In a Web-based attack scenario, an attacker would have to host a Web site that contains an 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 specially crafted Web site. Instead, an attacker would have to convince them to visit the Web site, typically by getting them to click a link that takes them to the attacker's site, and then convince them to open the specially crafted Excel file.
What systems are primarily at risk from the vulnerability?
Systems where Microsoft Office Excel is used, including workstations and terminal servers, are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.
What does the update do?
This update addresses the vulnerability by changing the way that Microsoft Office Excel parses specially crafted Excel files.
When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.
When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Excel Featheader Record Memory Corruption Vulnerability - CVE-2009-3129
A remote code execution vulnerability exists in the way that Microsoft Office Excel handles specially crafted Excel files that include a malformed record object. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2009-3129.
Mitigating Factors for Excel Featheader Record Memory Corruption Vulnerability - CVE-2009-3129
Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:
•
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.
•
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 impacted than users who operate with administrative user rights.
•
Users of Office XP and later editions of Office will be prompted with Open, Save, or Cancel before opening a document.
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Workarounds for Excel Featheader Record Memory Corruption Vulnerability - CVE-2009-3129
Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:
•
Use Microsoft Office File Block policy to block the opening of Office 2003 and earlier documents from unknown or untrusted sources and locations
The following registry scripts can be used to set the File Block policy.
Note Modifying the Registry incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from incorrect modification of the Registry can be solved. Modify the Registry at your own risk.
•
For Office 2003
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001
Note In order to use 'FileOpenBlock' with Office 2003, all of the latest Office 2003 security updates must be applied.
•
For Office 2007
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001
Note In order to use 'FileOpenBlock' with Office 2007, all of the latest Office 2007 security updates as of May 2007 must be applied.
Impact of workaround. Users who have configured the File Block policy and have not configured a special “exempt directory” as discussed in Microsoft Knowledge Base Article 922848 will be unable to open Office 2003 files or earlier versions in Office 2003 or 2007 Microsoft Office System.
How to undo the workaround:
•
For Office 2003
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
•
For Office 2007
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
•
Use the Microsoft Office Isolated Conversion Environment (MOICE) when opening files from unknown or untrusted sources
The Microsoft Office Isolated Conversion Environment (MOICE) will protect Office 2003 installations by more securely opening Word, Excel, and PowerPoint binary format files.
To install MOICE, you must have Office 2003 or 2007 Office system installed.
To install MOICE, you must have the Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats. The compatibility pack is available as a free download from the Microsoft Download Center:
Download the FileFormatConverters.exe package now
MOICE requires all updates that are recommended for all Office programs. Visit Microsoft Update to install all recommended updates:
http://update.microsoft.com/microsoftupdate/v6/default.aspx?ln=en-us
To enable MOICE, change the registered handler for the .xls, .xlt, and .xla file formats. The following table describes the command to enable or to disable MOICE for the .xls, .xlt, and .xla file formats:
Command to enable MOICE to be the registered handler Command to disable MOICE as the registered handler
ASSOC .XLS=oice.excel.sheet
ASSOC .xls=Excel.Sheet.8
ASSOC .XLT=oice.excel.template
ASSOC .xlt=Excel.Template
ASSOC .XLA=oice.excel.addin
ASSOC .xla=Excel.Addin
Note On Windows Vista and Windows Server 2008, the commands above will need to be run from an elevated command prompt.
For more information on MOICE, see Microsoft Knowledge Base Article 935865.
Impact of workaround. Office 2003 and earlier formatted documents that are converted to the 2007 Microsoft Office System Open XML format by MOICE will not retain macro functionality. Additionally, documents with passwords or that are protected with Digital Rights Management cannot be converted.
•
Do not open Excel files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for Excel Featheader Record Memory Corruption Vulnerability - CVE-2009-3129
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system remotely. An attacker could then install programs or view, change, or delete data; or create new accounts with full user rights.
What causes the vulnerability?
The vulnerability exists in the way that Microsoft Office Excel parses the Excel spreadsheet file format when opening a specially crafted Excel spreadsheet.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel spreadsheet with an affected version of Microsoft Office Excel.
In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially crafted Excel file to the user and by convincing the user to open the file.
In a Web-based attack scenario, an attacker would have to host a Web site that contains an 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 specially crafted Web site. Instead, an attacker would have to convince them to visit the Web site, typically by getting them to click a link that takes them to the attacker's site, and then convince them to open the specially crafted Excel file.
What systems are primarily at risk from the vulnerability?
Systems where Microsoft Office Excel is used, including workstations and terminal servers, are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.
What does the update do?
This update addresses the vulnerability by changing the way that Microsoft Office Excel parses specially crafted Excel files.
When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.
When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Excel Document Parsing Heap Overflow Vulnerability - CVE-2009-3130
A remote code execution vulnerability exists in the way Microsoft Office Excel handles specially crafted Excel files with malformed BIFF records. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2009-3130.
Mitigating Factors for Excel Document Parsing Heap Overflow Vulnerability - CVE-2009-3130
Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:
•
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.
•
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 impacted than users who operate with administrative user rights.
•
Users of Office XP and later editions of Office will be prompted with Open, Save, or Cancel before opening a document.
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Workarounds for Excel Document Parsing Heap Overflow Vulnerability - CVE-2009-3130
Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:
•
Do not open Excel files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for Excel Document Parsing Heap Overflow Vulnerability - CVE-2009-3130
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system remotely. An attacker could then install programs or view, change, or delete data; or create new accounts with full user rights.
What causes the vulnerability?
The vulnerability is caused by Excel not correctly handling Excel files with malformed Binary File Format (BIFF) records, which could result in the corruption of memory in such a way that an attacker could execute arbitrary code.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could cause arbitrary code to run with the privileges of the user who opened the file.
How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel spreadsheet with an affected version of Microsoft Office Excel.
In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially crafted Excel file to the user and by convincing the user to open the file.
In a Web-based attack scenario, an attacker would have to host a Web site that contains an 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 specially crafted Web site. Instead, an attacker would have to convince them to visit the Web site, typically by getting them to click a link that takes them to the attacker's site, and then convince them to open the specially crafted Excel file.
What systems are primarily at risk from the vulnerability?
Systems where Microsoft Office Excel is used, including workstations and terminal servers, are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.
What does the update do?
The update removes the vulnerability by modifying the way that Excel handles malformed BIFF records.
When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.
When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Excel Formula Parsing Memory Corruption Vulnerability - CVE-2009-3131
A remote code execution vulnerability exists in the way that Microsoft Office Excel parses documents containing a specially crafted formula embedded inside a cell. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights in the context of the currently logged on user.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2009-3131.
Mitigating Factors for Excel Formula Parsing Memory Corruption Vulnerability - CVE-2009-3131
Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:
•
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.
•
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 impacted than users who operate with administrative user rights.
•
Users of Office XP and later editions of Office will be prompted with Open, Save, or Cancel before opening a document.
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Workarounds for Excel Formula Parsing Memory Corruption Vulnerability - CVE-2009-3131
Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:
•
Do not open Excel files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for Excel Formula Parsing Memory Corruption Vulnerability - CVE-2009-3131
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system remotely. An attacker could then install programs or view, change, or delete data; or create new accounts with full user rights.
What causes the vulnerability?
The vulnerability exists in the way that Microsoft Office Excel parses the Excel spreadsheet containing a specially crafted formula.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
How could an attacker exploit the vulnerability?
This vulnerability requires that a user open a specially-crafted Excel file with an affected version of Microsoft Excel.
In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a malformed Excel file to the user and by convincing the user to open the file.
In a Web-based attack scenario, an attacker would have to host a Web site that contains an 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 specially crafted Web site. Instead, an attacker would have to convince users to visit the Web site, typically by getting them to click a link that takes them to the attacker's site.
What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel used, including workstations and terminal servers, are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.
What does the update do?
This update addresses the vulnerability by changing the way that Microsoft Office Excel parses specially crafted Excel files.
When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.
When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Excel Index Parsing Vulnerability - CVE-2009-3132
A remote code execution vulnerability exists in Microsoft Office Excel as a result of pointer corruption when loading Excel formulas. The vulnerability could allow remote code execution if a user opens a specially crafted Excel file that includes a malformed formula. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2009-3132.
Mitigating Factors for Excel Index Parsing Vulnerability - CVE-2009-3132
Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:
•
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.
•
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 impacted than users who operate with administrative user rights.
•
Users of Office XP and later editions of Office will be prompted with Open, Save, or Cancel before opening a document.
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Workarounds for Excel Index Parsing Vulnerability - CVE-2009-3132
Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:
•
Do not open Excel files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
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FAQ for Excel Index Parsing Vulnerability - CVE-2009-3132
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system remotely. An attacker could then install programs or view, change, or delete data; or create new accounts with full user rights.
What causes the vulnerability?
The vulnerability exists in the way Microsoft Office Excel parses the Excel spreadsheet file format when opening a specially crafted Excel spreadsheet.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel spreadsheet with an affected version of Microsoft Office Excel.
In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially crafted Excel file to the user and by convincing the user to open the file.
In a Web-based attack scenario, an attacker would have to host a Web site that contains an 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 specially crafted Web site. Instead, an attacker would have to convince them to visit the Web site, typically by getting them to click a link that takes them to the attacker's site, and then convince them to open the specially crafted Excel file.
What systems are primarily at risk from the vulnerability?
Systems where the Microsoft Office Excel is used, including workstations and terminal servers, are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this
What does the update do?
This update addresses the vulnerability by changing the way Microsoft Office Excel handles opening specially crafted Excel files.
When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.
When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Excel Document Parsing Memory Corruption Vulnerability - CVE-2009-3133
A remote code execution vulnerability exists in Microsoft Office Excel as a result of memory corruption when loading Excel records. The vulnerability could allow remote code execution if a user opens a specially crafted Excel file that includes a malformed object. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2009-3133.
Mitigating Factors for Excel Document Parsing Memory Corruption Vulnerability - CVE-2009-3133
Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:
•
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.
•
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 impacted than users who operate with administrative user rights.
•
Users of Office XP and later editions of Office will be prompted with Open, Save, or Cancel before opening a document.
Top of sectionTop of section
Workarounds for Excel Document Parsing Memory Corruption Vulnerability - CVE-2009-3133
Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:
•
Do not open Excel files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
Top of sectionTop of section
FAQ for Excel Document Parsing Memory Corruption Vulnerability - CVE-2009-3133
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system remotely. An attacker could then install programs or view, change, or delete data; or create new accounts with full user rights.
What causes the vulnerability?
The vulnerability exists in the way Microsoft Office Excel parses the Excel spreadsheet file format when opening a specially crafted Excel spreadsheet.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel spreadsheet with an affected version of Microsoft Office Excel.
In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially crafted Excel file to the user and by convincing the user to open the file.
In a Web-based attack scenario, an attacker would have to host a Web site that contains an 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 specially crafted Web site. Instead, an attacker would have to convince them to visit the Web site, typically by getting them to click a link that takes them to the attacker's site, and then convincing them to open the specially crafted Excel file.
What systems are primarily at risk from the vulnerability?
Systems where the Microsoft Office Excel is used, including workstations and terminal servers, are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.
What does the update do?
This update addresses the vulnerability by changing the way Microsoft Office Excel handles opening specially crafted Excel files
When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.
When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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Excel Field Sanitization Vulnerability - CVE-2009-3134
A remote code execution vulnerability exists in Microsoft Office Excel that could allow remote code execution if a user opens a specially crafted Excel file that includes a malformed record object. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2009-3134.
Mitigating Factors for Excel Field Sanitization Vulnerability - CVE-2009-3134
Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:
•
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.
•
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 impacted than users who operate with administrative user rights.
•
Users of Office XP and later editions of Office will be prompted with Open, Save, or Cancel before opening a document.
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Workarounds for Excel Field Sanitization Vulnerability - CVE-2009-3134
Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:
•
Use Microsoft Office File Block policy to block the opening of Office 2003 and earlier documents from unknown or untrusted sources and locations
The following registry scripts can be used to set the File Block policy.
Note Modifying the Registry incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from incorrect modification of the Registry can be solved. Modify the Registry at your own risk.
•
For Office 2003
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001
Note In order to use 'FileOpenBlock' with Office 2003, all of the latest Office 2003 security updates must be applied.
•
For Office 2007
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001
Note In order to use 'FileOpenBlock' with Office 2007, all of the latest Office 2007 security updates as of May 2007 must be applied.
Impact of workaround. Users who have configured the File Block policy and have not configured a special “exempt directory” as discussed in Microsoft Knowledge Base Article 922848 will be unable to open Office 2003 files or earlier versions in Office 2003 or 2007 Microsoft Office System.
How to undo the workaround:
•
For Office 2003
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
•
For Office 2007
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
•
Use the Microsoft Office Isolated Conversion Environment (MOICE) when opening files from unknown or untrusted sources
The Microsoft Office Isolated Conversion Environment (MOICE) will protect Office 2003 installations by more securely opening Word, Excel, and PowerPoint binary format files.
To install MOICE, you must have Office 2003 or 2007 Office system installed.
To install MOICE, you must have the Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats. The compatibility pack is available as a free download from the Microsoft Download Center:
Download the FileFormatConverters.exe package now
MOICE requires all updates that are recommended for all Office programs. Visit Microsoft Update to install all recommended updates:
http://update.microsoft.com/microsoftupdate/v6/default.aspx?ln=en-us
To enable MOICE, change the registered handler for the .xls, .xlt, and .xla file formats. The following table describes the command to enable or to disable MOICE for the .xls, .xlt, and .xla file formats:
Command to enable MOICE to be the registered handler Command to disable MOICE as the registered handler
ASSOC .XLS=oice.excel.sheet
ASSOC .xls=Excel.Sheet.8
ASSOC .XLT=oice.excel.template
ASSOC .xlt=Excel.Template
ASSOC .XLA=oice.excel.addin
ASSOC .xla=Excel.Addin
Note On Windows Vista and Windows Server 2008, the commands above will need to be run from an elevated command prompt.
For more information on MOICE, see Microsoft Knowledge Base Article 935865.
Impact of workaround. Office 2003 and earlier formatted documents that are converted to the 2007 Microsoft Office System Open XML format by MOICE will not retain macro functionality. Additionally, documents with passwords or that are protected with Digital Rights Management cannot be converted.
•
Do not open Excel files that you receive from untrusted sources or that you receive unexpectedly from trusted sources. This vulnerability could be exploited when a user opens a specially crafted file.
Top of sectionTop of section
FAQ for Excel Field Sanitization Vulnerability - CVE-2009-3134
What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system remotely. An attacker could then install programs or view, change, or delete data; or create new accounts with full user rights.
What causes the vulnerability?
The vulnerability exists in the way that Microsoft Office Excel parses the Excel spreadsheet file format when opening a specially crafted Excel spreadsheet.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel spreadsheet with an affected version of Microsoft Office Excel.
In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially crafted Excel file to the user and by convincing the user to open the file.
In a Web-based attack scenario, an attacker would have to host a Web site that contains an 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 specially crafted Web site. Instead, an attacker would have to convince them to visit the Web site, typically by getting them to click a link that takes them to the attacker's site, and then convince them to open the specially crafted Excel file.
What systems are primarily at risk from the vulnerability?
Systems where Microsoft Office Excel is used, including workstations and terminal servers, are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.
What does the update do?
This update addresses the vulnerability by changing the way that Microsoft Office Excel parses specially crafted Excel files.
When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.
When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
Other Information
Acknowledgments
Microsoft thanks the following for working with us to help protect customers:
•
Bing Liu of Fortinet's FortiGuard Labs for reporting the Excel Cache Memory Corruption Vulnerability (CVE-2009-3127)
•
TippingPoint and the Zero Day Initiative for reporting the Excel Cache Memory Corruption Vulnerability (CVE-2009-3127)
•
Bing Liu of Fortinet's FortiGuard Labs for reporting the Excel SxView Memory Corruption Vulnerability (CVE-2009-3128)
•
Sean Larsson of VeriSign iDefense Labs for reporting the Excel Featheader Record Memory Corruption Vulnerability (CVE-2009-3129)
•
An anonymous researcher, working with TippingPoint and the Zero Day Initiative, for reporting the Excel Featheader Record Memory Corruption Vulnerability (CVE-2009-3129)
•
Nicolas Joly of VUPEN Security for reporting the Excel Document Parsing Heap Overflow Vulnerability (CVE-2009-3130)
•
Nicolas Joly of VUPEN Security for reporting the Excel Formula Parsing Memory Corruption Vulnerability (CVE-2009-3131)
•
Nicolas Joly of VUPEN Security for reporting the Excel Index Parsing Vulnerability (CVE-2009-3132)
•
Nicolas Joly of VUPEN Security for reporting the Excel Document Parsing Memory Corruption Vulnerability (CVE-2009-3133)
•
Bing Liu of Fortinet's FortiGuard Labs for reporting the Excel Field Sanitization Vulnerability (CVE-2009-3134)
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Microsoft Active Protections Program (MAPP)
To improve security protections for customers, Microsoft provides vulnerability information to major security software providers in advance of each monthly security update release. Security software providers can then use this vulnerability information to provide updated protections to customers via their security software or devices, such as antivirus, network-based intrusion detection systems, or host-based intrusion prevention systems. To determine whether active protections are available from security software providers, please visit the active protections Web sites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.
Support
•
Customers in the U.S. and Canada can receive technical support from Security Support or 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates. For more information about available support options, see Microsoft Help and Support.
•
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.
Disclaimer
The information provided in the Microsoft Knowledge Base 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
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V1.0 (November 10, 2009): Bulletin published.
Related
