SecurityvulnsSECURITYVULNS:DOC:19382Microsoft Security Bulletin MS08-016 – Critical Vulnerabilities in Microsoft Office Could Allow Remote Code Execution (949030)
Microsoft Security Bulletin MS08-016 – Critical
Vulnerabilities in Microsoft Office Could Allow Remote Code Execution (949030)
Published: March 11, 2008
Version: 1.0
General Information
Executive Summary
This security update resolves two privately reported vulnerabilities in Microsoft Office that could allow remote code execution if a user opens a malformed Office file. 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. 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 Critical for supported editions of Microsoft Office 2000 and rated Important for supported editions of Microsoft Office XP, Microsoft Office 2003 Service Pack 2, Microsoft Excel Viewer 2003 and Microsoft Excel Viewer 2003 Service Pack 3, and Microsoft Office 2004 for Mac. For more information, see the subsection, Affected and Non-Affected Software, in this section.
This security update addresses these vulnerabilities by modifying the way that Microsoft Office allocates memory. 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 immediately
Known Issues. None
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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 Maximum Security Impact Aggregate Severity Rating Bulletins Replaced by this Update
Microsoft Office 2000 Service Pack 3
(KB947361)
Remote Code Execution
Critical
MS07-025
Microsoft Office XP Service Pack 3
(KB947866)
Remote Code Execution
Important
MS07-025
MS07-015
Microsoft Office 2003 Service Pack 2
(KB947355)
Remote Code Execution
Important
None
Microsoft Office Excel Viewer 2003
(KB947355)
Microsoft Office Excel Viewer 2003 Service Pack 3
(KB947355)
Remote Code Execution
Important
None
Microsoft Office 2004 for Mac
(KB949357)
Remote Code Execution
Important
MS08-013
Non-Affected Software
Office Suite and Other Software
Microsoft Office 2003 Service Pack 3
Microsoft PowerPoint Viewer 2003
Microsoft Visio 2002 Service Pack 2
Microsoft Visio 2003 Viewer
Microsoft Word Viewer 2003
Microsoft Project 2000 Service Pack 1
Microsoft Project 2002 Service Pack 2
2007 Microsoft Office System
2007 Microsoft Office System Service Pack 1
Microsoft Office 2008 for Mac
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Frequently Asked Questions (FAQ) Related to This Security Update
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. To determine the support life cycle for your software release, visit Microsoft Support Lifecycle.
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. For more information about the Windows Product Lifecycle, visit Microsoft Support Lifecycle. For more information about the extended security update support period for these software versions or editions, visit Microsoft Product Support Services.
Customers who require custom support for older releases 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 Microsoft Worldwide Information, select the country, 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 Windows Operating System Product Support Lifecycle FAQ.
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Vulnerability Information
Severity Ratings and Vulnerability Identifiers
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Microsoft Office Cell Parsing Memory Corruption Vulnerability – CVE-2008-0113 Microsoft Office Memory Corruption Vulnerability - CVE-2008-0118 Aggregate Severity Rating
Microsoft Office 2000 Service Pack 3
None
Critical
Remote Code Execution
Critical
Microsoft Office XP Service Pack 3
None
Important
Remote Code Execution
Important
Microsoft Office 2003 Service Pack 2
None
Important
Remote Code Execution
Important
Microsoft Office Excel Viewer 2003 and Microsoft Office Excel Viewer Service Pack 3
Important
Remote Code Execution
None
Important
Microsoft Office 2004 for Mac
None
Important
Remote Code Execution
Important
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Microsoft Office Cell Parsing Memory Corruption Vulnerability - CVE-2008-0113
A remote code execution vulnerability exists in the way Microsoft Office handles specially crafted Excel files. An attacker could exploit the vulnerability by creating a malformed file which could be included as an e-mail attachment, or hosted on a specially crafted or compromised Web site.
If a user were logged on with administrative user rights, 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. 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.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2008-0113.
Mitigating Factors for the Microsoft Office Cell Parsing Memory Corruption Vulnerability - CVE-2008-0113
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:
•
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.
•
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 in an e-mail message or Instant Messenger message that takes users 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. The features of the Office Document Open Confirmation Tool are incorporated in Office XP and Office 2003.
•
Microsoft Office 2003 Service Pack 3 is not affected by this vulnerability.
•
2007 Microsoft Office System is not affected by this vulnerability.
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Workarounds for the Microsoft Office Cell Parsing Memory Corruption Vulnerability - CVE-2008-0113
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 the Microsoft Office Isolated Conversion Environment (MOICE) when opening files from unknown or untrusted sources
The Microsoft Office Isolated Conversion Environment (MOICE) when added to the Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats is used to more securely open Word, Excel, and PowerPoint binary format files.
To install MOICE, you must have Office 2003 or 2007 Office 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 handle 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:
To enable MOICE, change the registered handle 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 use to enable MOICE to be the registered handler Command to use 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
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.
•
Use Microsoft Office File Block policy to prevent 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 or Service Pack 3 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:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
•
Do not open or save Microsoft Office 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 the Microsoft Office Cell Parsing Memory Corruption Vulnerability - CVE-2008-0113
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. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
What causes the vulnerability?
The vulnerability is caused by an allocation error when Microsoft Office opens a specially crafted Excel file. The error may corrupt system 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 take complete control of an affected system. 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 using an affected version of Microsoft Office.
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 Excel 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.
What systems are primarily at risk from the vulnerability?
Systems where Microsoft Office is used 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 Microsoft Office calculates the required memory allocation when opening Excel files.
When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued. This security bulletin addresses the privately disclosed vulnerability as well as additional issues discovered through internal investigations.
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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Microsoft Office Memory Corruption Vulnerability - CVE-2008-0118
A remote code execution vulnerability exists in the way Microsoft Office processes malformed Office files. An attacker could exploit the vulnerability by creating a malformed Office file which could be included as an e-mail attachment, or hosted on a specially crafted or compromised Web site.
If a user were logged on with administrative user rights, 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. 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.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2008-0118.
Mitigating Factors for the Microsoft Office Memory Corruption Vulnerability - CVE-2008-0118
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:
•
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.
•
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 in an e-mail message or Instant Messenger message 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. The features of the Office Document Open Confirmation Tool are incorporated in Office XP and Office 2003.
•
Microsoft Office 2003 Service Pack 3 is not affected by this vulnerability.
•
2007 Microsoft Office System is not affected by this vulnerability.
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Workarounds for the Microsoft Office Memory Corruption Vulnerability - CVE-2008-0118
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 the Microsoft Office Isolated Conversion Environment (MOICE) when opening files from unknown or untrusted sources
The Microsoft Office Isolated Conversion Environment (MOICE) when added to the Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats is used to more securely open Word, Excel, and PowerPoint binary format files.
To install MOICE, you must have Office 2003 or 2007 Office 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 handle for the .ppt, .pot, and .pps file formats. The following table describes the command to enable or to disable MOICE for the .doc, .xls, .xlt, .xla, .ppt, .pot, and .pps file formats:
To enable MOICE, change the registered handle for the .doc, .xls, .xlt, .xla, .ppt, .pot, and .pps file formats. The following table describes the command to enable or to disable MOICE for the .ppt, .pot, and .pps file formats:
Command to use to enable MOICE to be the registered handler Command to use to disable MOICE as the registered handler
ASSOC .doc=oice.word.document
ASSOC .doc=Word.Document.8
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
ASSOC .PPT=oice.powerpoint.show
ASSOC .ppt=PowerPoint.Show.8
ASSOC .POT=oice.powerpoint.template
ASSOC .pot=PowerPoint.Template.8
ASSOC .PPS=oice.powerpoint.slideshow
ASSOC .pps=PowerPoint.SlideShow.8
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.
•
Use Microsoft Office File Block policy to prevent 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\PowerPoint\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Word\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001
[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 or Service Pack 3 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:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\PowerPoint\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Word\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
•
Do not open or save Microsoft Office 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 PowerPoint file.
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FAQ for the Microsoft Office Memory Corruption Vulnerability - CVE-2008-0118
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. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
What causes the vulnerability?
The vulnerability is caused by an allocation error when Microsoft Office opens a specially crafted Office file. The error may corrupt system 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 take complete control of an affected system. 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 Office file using an affected version of Microsoft Office.
In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially-crafted Office 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 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 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.
What systems are primarily at risk from the vulnerability?
Systems where Microsoft Office is used 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 Microsoft Office calculates the required memory allocation when opening Office files.
When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued. This security bulletin addresses the privately disclosed vulnerability as well as additional issues discovered through internal investigations.
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:
•
Arnaud Dovi, working with Zero Day Initiative, for reporting the Microsoft Office Cell Parsing Vulnerability (CVE-2008-0113)
•
An anonymous finder for reporting the Microsoft Office Memory Corruption Vulnerability (CVE-208-0118)
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Support
•
Customers in the U.S. and Canada 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.
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
•
V1.0 (March 11, 2008): Bulletin published.
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