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Related information

  Microsoft Excel multiple security vulnerabilities

  iDefense Security Advisory 06.11.09: Microsoft Excel SST Record Integer Overflow Vulnerability

  ZDI-09-040: Microsoft Office Excel QSIR Record Pointer Corruption Vulnerability

  Secunia Research: Microsoft Excel Record Parsing Array Indexing Vulnerability

  Secunia Research: Microsoft Excel String Parsing Integer Overflow Vulnerability

From:MICROSOFT <secure_(at)_microsoft.com>
Date:10.06.2009
Subject:Microsoft Security Bulletin MS09-021 - Critical Vulnerabilities in Microsoft Office Excel Could Allow Remote Code Execution (969462)

Microsoft Security Bulletin MS09-021 - Critical
Vulnerabilities in Microsoft Office Excel Could Allow Remote Code Execution (969462)
Published: June 9, 2009

Version: 1.0
General Information
Executive Summary

This security update resolves several privately reported vulnerabilities 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 any of these vulnerabilities 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.

This security update is rated Critical for all supported editions of Microsoft Office Excel 2000. 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, this security update is rated Important.

The update addresses the vulnerabilities by modifying the way that Excel parses Excel files. 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 Component Maximum Security Impact Aggregate Severity Rating Bulletins Replaced by this Update
Microsoft Office Suites and Components

Microsoft Office 2000 Service Pack 3


Microsoft Office Excel 2000 Service Pack 3
(KB969683)


Remote Code Execution


Critical


MS09-009

Microsoft Office XP Service Pack 3


Microsoft Office Excel 2002 Service Pack 3
(KB969680)


Remote Code Execution


Important


MS09-009

Microsoft Office 2003 Service Pack 3


Microsoft Office Excel 2003 Service Pack 3
(KB969681)


Remote Code Execution


Important


MS09-009

2007 Microsoft Office System Service Pack 1


Microsoft Office Excel 2007 Service Pack 1*
(KB969682)


Remote Code Execution


Important


MS09-009

2007 Microsoft Office System Service Pack 2


Microsoft Office Excel 2007 Service Pack 2*
(KB969682)


Remote Code Execution


Important


None
Microsoft Office for Mac

Microsoft Office 2004 for Mac
(KB969661)


Not applicable


Remote Code Execution


Important


MS09-009

Microsoft Office 2008 for Mac
(KB971822)


Not applicable


Remote Code Execution


Important


MS09-009

Open XML File Format Converter for Mac
(KB971824)


Not applicable


Remote Code Execution


Important


MS08-074
Other Office Software

Microsoft Office Excel Viewer 2003 Service Pack 3
(KB969685)


Not applicable


Remote Code Execution


Important


MS09-009

Microsoft Office Excel Viewer
(KB969686)


Not applicable


Remote Code Execution


Important


MS09-009

Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 1
(KB969679)


Not applicable


Remote Code Execution


Important


MS09-009

Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 2
(KB969679)


Not applicable


Remote Code Execution


Important


None

Microsoft Office SharePoint Server 2007 Service Pack 1 (32-bit editions)**
(KB969737)


Not applicable


Remote Code Execution


Important


MS08-057

Microsoft Office SharePoint Server 2007 Service Pack 2 (32-bit editions)**
(KB969737)


Not applicable


Remote Code Execution


Important


None

Microsoft Office SharePoint Server 2007 Service Pack 1 (64-bit editions)**
(KB969737)


Not applicable


Remote Code Execution


Important


MS08-057

Microsoft Office SharePoint Server 2007 Service Pack 2 (64-bit editions)**
(KB969737)


Not applicable


Remote Code Execution


Important


None

*For Microsoft Office Excel 2007 Service Pack 1 and Microsoft Office Excel 2007 Service Pack 2, in addition to security update package KB969682, 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 (KB969679) to be protected from the vulnerabilities described in this bulletin.

**This update applies to servers that have Excel Services installed, such as the default configuration of Microsoft Office SharePoint Server 2007 Enterprise and Microsoft Office SharePoint Server 2007 For Internet Sites. Microsoft Office SharePoint Server 2007 Standard does not include Excel Services.

Non-Affected Software
Office and Other Software

Microsoft Office Converter Pack

Works 8.5

Works 9
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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.

MS09-017 and MS09-027 also describe vulnerabilities in Microsoft Office 2004 for Mac, Microsoft Office 2008 for Mac, and Open XML File Format Converter for Mac. How do MS09-017 and MS09-027 relate to this bulletin (MS09-021)?
The security update packages for Microsoft Office 2004 for Mac (KB969661), Microsoft Office 2008 for Mac (KB971822), and Open XML File Format Converter for Mac (KB971824) in this bulletin, MS09-021, also address the vulnerabilities described in MS09-017 and MS09-027. 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 the update packages once.

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.

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

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 June bulletin summary. For more information, see Microsoft Exploitability Index.
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Record Pointer Corruption Vulnerability - CVE-2009-0549 Object Record Corruption Vulnerability - CVE-2009-0557 Array Indexing Memory Corruption Vulnerability - CVE-2009-0558 String Copy Stack-Based Overrun Vulnerability - CVE-2009-0559 Field Sanitization Memory Corruption Vulnerability - CVE-2009-0560 Record Integer Overflow Vulnerability - CVE-2009-0561 Record Pointer Corruption Vulnerability - CVE-2009-1134 Aggregate Severity Rating
Microsoft Office Suites and Components

Microsoft Office Excel 2000 Service Pack 3


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical
Remote Code Execution


Critical
Remote Code Execution


Not applicable


Critical

Microsoft Office Excel 2002 Service Pack 3


Important
Remote Code Execution


Important
Remote Code Execution


Not applicable


Important
Remote Code Execution


Important
Remote Code Execution


Important
Remote Code Execution


Not applicable


Important

Microsoft Office Excel 2003 Service Pack 3


Important
Remote Code Execution


Important
Remote Code Execution


Not applicable


Not applicable


Important
Remote Code Execution


Important
Remote Code Execution


Not applicable


Important

Microsoft Office Excel 2007 Service Pack 1


Not applicable


Important
Remote Code Execution


Not applicable


Not applicable


Important
Remote Code Execution


Important
Remote Code Execution


Important
Remote Code Execution


Important

Microsoft Office Excel 2007 Service Pack 2


Not applicable


Important
Remote Code Execution


Not applicable


Not applicable


Important
Remote Code Execution


Important
Remote Code Execution


Important
Remote Code Execution


Important
Microsoft Office for Mac

Microsoft Office for Mac 2004


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

Microsoft Office for Mac 2008


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

Microsoft Office Open XML File Converter for MAC


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
Other Office Software

Microsoft Office Excel Viewer 2003 Service Pack 3


Important
Remote Code Execution


Important
Remote Code Execution


Not applicable


Not applicable


Important
Remote Code Execution


Important
Remote Code Execution


Not applicable


Important

Microsoft Office Excel Viewer


Not applicable


Important
Remote Code Execution


Not applicable


Not applicable


Important
Remote Code Execution


Important
Remote Code Execution


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


Important
Remote Code Execution


Not applicable


Not applicable


Important
Remote Code Execution


Important
Remote Code Execution


Moderate
Remote Code Execution


Important

Microsoft Office SharePoint Server 2007 Service Pack 1 and Microsoft Office SharePoint Server 2007 Service Pack 2 (32-bit editions)


Not applicable


Not applicable


Not applicable


Not applicable


Not applicable


Important
Remote Code Execution


Not applicable


Important

Microsoft Office SharePoint Server 2007 Service Pack 1 and Microsoft Office SharePoint Server 2007 Service Pack 2 (64-bit editions)


Not applicable


Not applicable


Not applicable


Not applicable


Not applicable


Important
Remote Code Execution


Not applicable


Important
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Record Pointer Corruption Vulnerability - CVE-2009-0549

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-2009-0549.

Mitigating Factors for Record Pointer Corruption Vulnerability - CVE-2009-0549

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 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 later editions of Office.
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Workarounds for Record Pointer Corruption Vulnerability - CVE-2009-0549

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) 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.


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


Do not open or save 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 Record Pointer Corruption Vulnerability - CVE-2009-0549

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 that could allow remote code execution 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?
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. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received 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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Object Record Corruption Vulnerability - CVE-2009-0557

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-2009-0557.

Mitigating Factors for Object Record Corruption Vulnerability - CVE-2009-0557

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 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 later editions of Office.
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Workarounds for Object Record Corruption Vulnerability - CVE-2009-0557

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 un-trusted 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 or save 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 Object Record Corruption Vulnerability - CVE-2009-0557

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 that could allow remote code execution 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?
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. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received 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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Array Indexing Memory Corruption Vulnerability - CVE-2009-0558

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-2009-0558.

Mitigating Factors for Array Indexing Memory Corruption Vulnerability - CVE-2009-0558

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 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 later editions of Office.
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Workarounds for Array Indexing Memory Corruption Vulnerability - CVE-2009-0558

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 or save 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 Array Indexing Memory Corruption Vulnerability - CVE-2009-0558

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 that could allow remote code execution 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?
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. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received 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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String Copy Stack-Based Overrun Vulnerability - CVE-2009-0559

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-2009-0559.

Mitigating Factors for String Copy Stack-Based Overrun Vulnerability - CVE-2009-0559

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 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 later editions of Office.
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Workarounds for String Copy Stack-Based Overrun Vulnerability - CVE-2009-0559

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 or save 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 String Copy Stack-Based Overrun Vulnerability - CVE-2009-0559

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 that could allow remote code execution 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?
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. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received 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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Field Sanitization Memory Corruption Vulnerability - CVE-2009-0560

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-2009-0560.

Mitigating Factors for Field Sanitization Memory Corruption Vulnerability - CVE-2009-0560

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 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 later editions of Office.
Top of sectionTop of section

Workarounds for Field Sanitization Memory Corruption Vulnerability - CVE-2009-0560

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) 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.


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 2007 Office system

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\12.
0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001

Note In order to use 'FileOpenBlock' with the 2007 Microsoft Office system, all of the latest security updates for the 2007 Microsoft Office system 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 2007 Office system

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\12.
0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000
Top of sectionTop of section

FAQ for Field Sanitization Memory Corruption Vulnerability - CVE-2009-0560

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 that could allow remote code execution 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?
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. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received 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.
Top of sectionTop of section
Top of sectionTop of section

Record Integer Overflow Vulnerability - CVE-2009-0561

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-2009-0561.

Mitigating Factors for Record Integer Overflow Vulnerability - CVE-2009-0561

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 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 later editions of Office.
Top of sectionTop of section

Workarounds for Record Integer Overflow Vulnerability - CVE-2009-0561

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) 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.


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 2007 Office system

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\12.
0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001

Note In order to use 'FileOpenBlock' with the 2007 Microsoft Office system, all of the latest security updates for the 2007 Microsoft Office system 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 2007 Office system

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\12.
0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000


Do not open or save 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 Record Integer Overflow Vulnerability - CVE-2009-0561

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 that could allow remote code execution 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?
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. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received 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.
Top of sectionTop of section
Top of sectionTop of section

Record Pointer Corruption Vulnerability - CVE-2009-1134

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-2009-1134.

Mitigating Factors for Record Pointer Corruption Vulnerability - CVE-2009-1134

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 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 later editions of Office.
Top of sectionTop of section

Workarounds for Record Pointer Corruption Vulnerability - CVE-2009-1134

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) 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.


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 2007 Office system

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\12.
0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000001

Note In order to use 'FileOpenBlock' with the 2007 Microsoft Office system, all of the latest security updates for the 2007 Microsoft Office system 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 2007 Office system

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Office\12.
0\Excel\Security\FileOpenBlock]
"BinaryFiles"=dword:00000000


Do not open or save 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 Record Pointer Corruption Vulnerability - CVE-2009-1134

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 that could allow remote code execution 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?
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. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received 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 Global Security Research Team for reporting the Pointer Corruption Vulnerability (CVE-2009-0549)


Bing Liu of Fortinet's FortiGuard Global Security Research Team for reporting the Object Record Corruption Vulnerability (CVE-2009-0557)


Carsten H. Eiram of Secunia for reporting the Array Indexing Memory Corruption Vulnerability (CVE-2009-0558)


TELUS Security Labs Vulnerability Research Team for reporting the String Copy Stack-Based Overrun Vulnerability (CVE-2009-0559)


Bing Liu of Fortinet's FortiGuard Global Security Research Team for reporting the Field Sanitization Memory Corruption Vulnerability (CVE-2009-0560)


Sean Larsson and Joshua Drake of VeriSign iDefense Labs for reporting the Record Integer Overflow Vulnerability (CVE-2009-0561)


Carsten H. Eiram of Secunia for reporting the Record Integer Overflow Vulnerability (CVE-2009-0561)


TippingPoint and the Zero Day Initiative, for reporting the Record Pointer Corruption Vulnerability (CVE-2009-1134)
Top of sectionTop of section
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


V1.0 (June 9, 2009): Bulletin published.

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