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HistoryOct 13, 2010 - 12:00 a.m.

Microsoft Security Bulletin MS10-080 - Important Vulnerabilities in Microsoft Excel Could Allow Remote Code Execution (2293211)

2010-10-1300:00:00
vulners.com
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Microsoft Security Bulletin MS10-080 - Important
Vulnerabilities in Microsoft Excel Could Allow Remote Code Execution (2293211)
Published: October 12, 2010

Version: 1.0
General Information
Executive Summary

This security update resolves thirteen privately reported vulnerabilities in Microsoft Office. The vulnerabilities could allow remote code execution if a user opens a specially crafted Excel file or a specially crafted Lotus 1-2-3 file. An attacker who successfully exploited any of these vulnerabilities could gain the same user rights as the local user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

This security update is rated Important for all supported editions of Microsoft Excel 2002, Microsoft Excel 2003, Microsoft 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. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The update addresses the vulnerabilities by changing the way that Microsoft Office Excel parses specially crafted Excel files and specially crafted Lotus 1-2-3 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 at the earliest opportunity.

Known Issues. Microsoft Knowledge Base Article 2293211 documents the currently known issues that customers may experience when installing this security update. The article also documents recommended solutions for these issues. When currently known issues and recommended solutions pertain only to specific releases of this software, this article provides links to further articles.
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Affected and Non-Affected Software

The following software have been tested to determine which versions or editions are affected. Other versions or editions are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, visit Microsoft Support Lifecycle.

Affected Software
Microsoft Office Suite and Other Software Component Maximum Security Impact Aggregate Severity Rating Bulletins Replaced by this Update
Microsoft Office Suites and Components

Microsoft Office XP Service Pack 3

Microsoft Excel 2002 Service Pack 3
(KB2345017)

Remote Code Execution

Important

MS10-057

Microsoft Office 2003 Service Pack 3

Microsoft Excel 2003 Service Pack 3
(KB2344893)

Remote Code Execution

Important

MS10-057

Microsoft Office 2007 Service Pack 2

Microsoft Excel 2007 Service Pack 2[1]
(KB2345035)

Remote Code Execution

Important

MS10-038
Microsoft Office for Mac

Microsoft Office 2004 for Mac
(KB2422343)

Not applicable

Remote Code Execution

Important

MS10-057

Microsoft Office 2008 for Mac
(KB2422352)

Not applicable

Remote Code Execution

Important

MS10-057

Open XML File Format Converter for Mac
(KB2422398)

Not applicable

Remote Code Execution

Important

MS10-057
Other Microsoft Office Software

Microsoft Excel Viewer Service Pack 2
(KB2345088)

Not applicable

Remote Code Execution

Important

MS10-038

Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 2
(KB2344875)

Not applicable

Remote Code Execution

Important

MS10-038

[1]For Microsoft Office Excel 2007 Service Pack 2, in addition to security update package KB2345035, customers also need to install the security update for Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats Service Pack 2 (KB2344875) to be protected from the vulnerabilities described in this bulletin.

Non-Affected Software
Office and Other Software

Microsoft Excel 2010 (32-bit editions)

Microsoft Excel 2010 (64-bit editions)

Microsoft 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.

Why is this update only Important for all affected versions of Excel?
Microsoft Excel 2002 and later versions have a built-in feature that prompts a user to Open, Save, or Cancel before opening a document. This mitigating factor reduces the vulnerability from Critical to Important because the vulnerability requires more than a single user action to complete the exploit.

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.

MS10-079 also describes vulnerabilities in Microsoft Office 2004 for Mac, Microsoft Office 2008 for Mac, and Open XML File Format Converter for Mac. How does MS10-079 relate to this bulletin (MS10-080)?
The security update packages in this bulletin, MS10-080, for Microsoft Office 2004 for Mac (KB2422343), Microsoft Office 2008 for Mac (KB2422352), and Open XML File Format Converter for Mac (KB2422398) also address the vulnerabilities described in MS10-079. Users with Microsoft Office 2004 for Mac, Microsoft Office 2008 for Mac, or Open XML File Format Converter for Mac installed will only need to install these security update packages once.

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.

How are Microsoft Office standalone programs affected by the vulnerabilities?
A Microsoft Office standalone program is affected with the same severity rating as the corresponding component in a Microsoft Office Suite. For example, a standalone installation of Microsoft Excel is affected with the same severity rating as an installation of Microsoft Excel that was delivered with a Microsoft Office Suite.

What is the Microsoft Excel Viewer?
The Microsoft 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.

The Microsoft Office component discussed in this article is part of the Microsoft Office Suite that I have installed on my system; however, I did not choose to install this specific component. Will I be offered this update?
Yes, if the component discussed in this bulletin was delivered with the version of the Microsoft Office Suite installed on your system, the system will be offered updates for it whether the component is installed or not. The detection logic used to scan for affected systems is designed to check for updates for all components that were delivered with the particular Microsoft Office Suite and to offer the updates to a system. Users who choose not to apply an update for a component that is not installed, but is delivered with their version of the Microsoft Office Suite, will not increase the security risk of that system. On the other hand, users who do choose to install the update will not have a negative impact on the security or performance of a system.

Does the offer to update a non-vulnerable version of Microsoft Office constitute an issue in the Microsoft update mechanism?
No, the update mechanism is functioning correctly in that it detects a lower version of the files on the system than in the update package and thus, offers the update.

I am using an older release of the software discussed in this security bulletin. What should I do?
The affected software listed in this bulletin have been tested to determine which releases are affected. Other releases are past their support life cycle. For more information about the product lifecycle, visit the Microsoft Support Lifecycle Web site.

It should be a priority for customers who have older releases of the software to migrate to supported releases to prevent potential exposure to vulnerabilities. To determine the support lifecycle for your software release, see Select a Product for Lifecycle Information. For more information about service packs for these software releases, see Lifecycle Supported Service Packs.

Customers who require custom support for older software must contact their Microsoft account team representative, their Technical Account Manager, or the appropriate Microsoft partner representative for custom support options. Customers without an Alliance, Premier, or Authorized Contract can contact their local Microsoft sales office. For contact information, visit the Microsoft Worldwide Information Web site, select the country in the Contact Information list, and then click Go to see a list of telephone numbers. When you call, ask to speak with the local Premier Support sales manager. For more information, see the Microsoft Support Lifecycle Policy FAQ.
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Vulnerability Information

Severity Ratings and Vulnerability Identifiers

The following severity ratings assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin's release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the October bulletin summary. For more information, see Microsoft Exploitability Index.
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Excel Record Parsing Integer Overflow Vulnerability - CVE-2010-3230 Excel Record Parsing Memory Corruption Vulnerability - CVE-2010-3231 Excel File Format Parsing Vulnerability - CVE-2010-3232 Lotus 1-2-3 Workbook Parsing Vulnerability - CVE-2010-3233 Formula Substream Memory Corruption Vulnerability - CVE-2010-3234 Formula Biff Record Vulnerability - CVE-2010-3235 Out Of Bounds Array Vulnerability - CVE-2010-3236 Merge Cell Record Pointer Vulnerability - CVE-2010-3237 Negative Future Function Vulnerability - CVE-2010-3238 Extra Out of Boundary Record Parsing Vulnerability - CVE-2010-3239 Real Time Data Array Record Vulnerability - CVE-2010-3240 Out-of-Bounds Memory Write in Parsing Vulnerability - CVE-2010-3241 Ghost Record Type Parsing Vulnerability - CVE-2010-3242 Aggregate Severity Rating
Microsoft Office Suites and Components

Microsoft 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

Important
Remote Code Execution

Important
Remote Code Execution

Important
Remote Code Execution

Important
Remote Code Execution

Important
Remote Code Execution

Important
Remote Code Execution

Important
Remote Code Execution

Important
Remote Code Execution

Microsoft Excel 2003 Service Pack 3

Not applicable

Not applicable

Important
Remote Code Execution

Moderate
Remote Code Execution

Not applicable

Not applicable

Important
Remote Code Execution

Not applicable

Important
Remote Code Execution

Not applicable

Not applicable

Not applicable

Not applicable

Important
Remote Code Execution

Microsoft Excel 2007 Service Pack 2

Not applicable

Not applicable

Important
Remote Code Execution

Not applicable

Not applicable

Not applicable

Not applicable

Not applicable

Not applicable

Not applicable

Important
Remote Code Execution

Not applicable

Not applicable

Important
Remote Code Execution
Microsoft Office for Mac

Microsoft Office 2004 for Mac

Not applicable

Important
Remote Code Execution

Important
Remote Code Execution

Not applicable

Not applicable

Not applicable

Important
Remote Code Execution

Important
Remote Code Execution

Important
Remote Code Execution

Not applicable

Not applicable

Important
Remote Code Execution

Important
Remote Code Execution

Important
Remote Code Execution

Microsoft Office 2008 for Mac

Not applicable

Important
Remote Code Execution

Important
Remote Code Execution

Not applicable

Not applicable

Not applicable

Important
Remote Code Execution

Not applicable

Not applicable

Not applicable

Not applicable

Important
Remote Code Execution

Important
Remote Code Execution

Important
Remote Code Execution

Open XML File Format Converter for Mac

Not applicable

Important
Remote Code Execution

Important
Remote Code Execution

Not applicable

Not applicable

Not applicable

Important
Remote Code Execution

Not applicable

Not applicable

Not applicable

Not applicable

Important
Remote Code Execution

Important
Remote Code Execution

Important
Remote Code Execution
Other Microsoft Office Software

Microsoft Excel Viewer Service Pack 2

Not applicable

Not applicable

Important
Remote Code Execution

Not applicable

Not applicable

Not applicable

Not applicable

Not applicable

Not applicable

Not applicable

Important
Remote Code Execution

Not applicable

Not applicable

Important
Remote Code Execution

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

Not applicable

Not applicable

Important
Remote Code Execution

Not applicable

Not applicable

Not applicable

Not applicable

Not applicable

Not applicable

Not applicable

Important
Remote Code Execution

Not applicable

Not applicable

Important
Remote Code Execution
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Excel Record Parsing Integer Overflow Vulnerability - CVE-2010-3230

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3230.

Mitigating Factors for Excel Record Parsing Integer Overflow Vulnerability - CVE-2010-3230

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Excel Record Parsing Integer Overflow Vulnerability - CVE-2010-3230

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 Microsoft Office files from untrusted sources

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 Excel Record Parsing Integer Overflow Vulnerability - CVE-2010-3230

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?
When Microsoft Excel validates record information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates record information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Excel Record Parsing Memory Corruption Vulnerability - CVE-2010-3231

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3231.

Mitigating Factors for Excel Record Parsing Memory Corruption Vulnerability - CVE-2010-3231

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Excel Record Parsing Memory Corruption Vulnerability - CVE-2010-3231

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 Microsoft Office files from untrusted sources

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 Excel Record Parsing Memory Corruption Vulnerability - CVE-2010-3231

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?
When Microsoft Excel validates record information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates record information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Excel File Format Parsing Vulnerability - CVE-2010-3232

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3232.

Mitigating Factors for Excel File Format Parsing Vulnerability - CVE-2010-3232

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Excel File Format Parsing Vulnerability - CVE-2010-3232

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

Use Microsoft Office File Block policy to block the opening of Office 2003 and earlier documents from unknown or untrusted sources and locations

The following registry scripts can be used to set the File Block policy.

Note Modifying the Registry incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from incorrect modification of the Registry can be solved. Modify the Registry at your own risk.

For Office 2003

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]

"BinaryFiles"=dword:00000001

Note In order to use 'FileOpenBlock' with Microsoft Office 2003, all of the latest security updates for Microsoft Office 2003 must be applied.

For Office 2007

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Excel\Security\FileOpenBlock]

"BinaryFiles"=dword:00000001

Note In order to use 'FileOpenBlock' with 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 Office 2007.

How to undo the workaround.

For Office 2003

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]

"BinaryFiles"=dword:00000000

For Office 2007

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Excel\Security\FileOpenBlock]

"BinaryFiles"=dword:00000000

Use the Microsoft Office Isolated Conversion Environment (MOICE) when opening files from unknown or untrusted sources

The Microsoft Office Isolated Conversion Environment (MOICE) helps protect Office 2003 installations by more securely opening Word, Excel, and PowerPoint binary format files.

To install MOICE, you must have Office 2003 or Office 2007 installed.

To install MOICE, you must also 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

Enable MOICE

Note See Microsoft Knowledge Base Article 935865 to use the automated Microsoft Fix it solution to enable or disable this workaround.

To manually enable MOICE, run the commands as specified in the following table. Running the commands will associate the Office application extensions with MOICE.
Command to enable MOICE to be the registered handler

For Word, run the following command from a command prompt:
ASSOC .doc=oice.word.document

For Excel, run the following commands from a command prompt:
ASSOC .XLS=oice.excel.sheet
ASSOC .XLT=oice.excel.template
ASSOC .XLA=oice.excel.addin

For PowerPoint, run the following commands from a command prompt:
ASSOC .PPT=oice.powerpoint.show
ASSOC .POT=oice.powerpoint.template
ASSOC .PPS=oice.powerpoint.slideshow

Note On Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, run the above commands 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 Microsoft Office 2007 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.

How to undo the workaround. Run the commands to disable MOICE as specified in the table below.
Command to disable MOICE as the registered handler

For Word, run the following command from a command prompt:
ASSOC .doc=Word.Document.8

For Excel, run the following commands from a command prompt:
ASSOC .xls=Excel.Sheet.8
ASSOC .xlt=Excel.Template
ASSOC .xla=Excel.Addin

For PowerPoint, run the following commands from a command prompt:
ASSOC .ppt=PowerPoint.Show.8
ASSOC .PPS=oice.powerpoint.slideshow
ASSOC .pps=PowerPoint.SlideShow.8

Note On Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, run the above commands from an elevated command prompt.

Do not open Microsoft Office files from untrusted sources

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 Excel File Format Parsing Vulnerability - CVE-2010-3232

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?
When Microsoft Excel validates record information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates record information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Lotus 1-2-3 Workbook Parsing Vulnerability - CVE-2010-3233

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Lotus 1-2-3 workbook files (.wk3). 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-2010-3233.

Mitigating Factors for Lotus 1-2-3 Workbook Parsing Vulnerability - CVE-2010-3233

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Lotus 1-2-3 file.
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Workarounds for Lotus 1-2-3 Workbook Parsing Vulnerability - CVE-2010-3233

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 Microsoft Office files from untrusted sources

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 Lotus 1-2-3 Workbook Parsing Vulnerability - CVE-2010-3233

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?
When Microsoft Excel parses a specially crafted Lotus 1-2-3 file, system memory may become corrupted in such a way that an attacker could execute arbitrary code.

Why is this vulnerability rated Moderate on Microsoft Excel 2003 Service Pack 3?
By default, the opening of Lotus 1-2-3 files is blocked in Microsoft Excel 2003 Service Pack 3. This mitigating factor lowers the severity rating for CVE-2010-3233 on Microsoft Excel 2003 Service Pack 3. For more information about file types that are blocked after installing Microsoft Office 2003 Service Pack 3, see Microsoft Knowledge Base Article 938810.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Lotus 1-2-3 file with an affected version of Microsoft Excel.

In an e-mail attack scenario, an attacker could exploit the vulnerability by sending a specially crafted Lotus 1-2-3 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 Lotus 1-2-3 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 Lotus 1-2-3 file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates record information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Formula Substream Memory Corruption Vulnerability - CVE-2010-3234

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3234.

Mitigating Factors for Formula Substream Memory Corruption Vulnerability - CVE-2010-3234

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Formula Substream Memory Corruption Vulnerability - CVE-2010-3234

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 Microsoft Office files from untrusted sources

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.
Top of sectionTop of section

FAQ for Formula Substream Memory Corruption Vulnerability - CVE-2010-3234

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?
When Microsoft Excel validates formula information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 Excel validates formula information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Formula Biff Record Vulnerability - CVE-2010-3235

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3235.

Mitigating Factors for Formula Biff Record Vulnerability - CVE-2010-3235

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Formula Biff Record Vulnerability - CVE-2010-3235

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 Microsoft Office files from untrusted sources

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.
Top of sectionTop of section

FAQ for Formula Biff Record Vulnerability - CVE-2010-3235

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?
When Microsoft Excel validates formula information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates formula information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Out Of Bounds Array Vulnerability - CVE-2010-3236

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3236.

Mitigating Factors for Out Of Bounds Array Vulnerability - CVE-2010-3236

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Out Of Bounds Array Vulnerability - CVE-2010-3236

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

Use Microsoft Office File Block policy to block the opening of Office 2003 and earlier documents from unknown or untrusted sources and locations

The following registry scripts can be used to set the File Block policy.

Note Modifying the Registry incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from incorrect modification of the Registry can be solved. Modify the Registry at your own risk.

For Office 2003

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]

"BinaryFiles"=dword:00000001

Note In order to use 'FileOpenBlock' with Microsoft Office 2003, all of the latest security updates for Microsoft Office 2003 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.

How to undo the workaround.

For Office 2003

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]

"BinaryFiles"=dword:00000000

Use the Microsoft Office Isolated Conversion Environment (MOICE) when opening files from unknown or untrusted sources

The Microsoft Office Isolated Conversion Environment (MOICE) helps protect Office 2003 installations by more securely opening Word, Excel, and PowerPoint binary format files.

To install MOICE, you must have Office 2003 or Office 2007 installed.

To install MOICE, you must also 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

Enable MOICE

Note See Microsoft Knowledge Base Article 935865 to use the automated Microsoft Fix it solution to enable or disable this workaround.

To manually enable MOICE, run the commands as specified in the following table. Running the commands will associate the Office application extensions with MOICE.
Command to enable MOICE to be the registered handler

For Word, run the following command from a command prompt:
ASSOC .doc=oice.word.document

For Excel, run the following commands from a command prompt:
ASSOC .XLS=oice.excel.sheet
ASSOC .XLT=oice.excel.template
ASSOC .XLA=oice.excel.addin

For PowerPoint, run the following commands from a command prompt:
ASSOC .PPT=oice.powerpoint.show
ASSOC .POT=oice.powerpoint.template
ASSOC .PPS=oice.powerpoint.slideshow

Note On Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, run the above commands 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 Microsoft Office 2007 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.

How to undo the workaround. Run the commands to disable MOICE as specified in the table below.
Command to disable MOICE as the registered handler

For Word, run the following command from a command prompt:
ASSOC .doc=Word.Document.8

For Excel, run the following commands from a command prompt:
ASSOC .xls=Excel.Sheet.8
ASSOC .xlt=Excel.Template
ASSOC .xla=Excel.Addin

For PowerPoint, run the following commands from a command prompt:
ASSOC .ppt=PowerPoint.Show.8
ASSOC .PPS=oice.powerpoint.slideshow
ASSOC .pps=PowerPoint.SlideShow.8

Note On Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, run the above commands from an elevated command prompt.

Do not open Microsoft Office files from untrusted sources

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 Out Of Bounds Array Vulnerability - CVE-2010-3236

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?
When Microsoft Excel validates record information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 Excel validates record information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Merge Cell Record Pointer Vulnerability - CVE-2010-3237

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3237.

Mitigating Factors for Merge Cell Record Pointer Vulnerability - CVE-2010-3237

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Merge Cell Record Pointer Vulnerability - CVE-2010-3237

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 Microsoft Office files from untrusted sources

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.
Top of sectionTop of section

FAQ for Merge Cell Record Pointer Vulnerability - CVE-2010-3237

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?
When Microsoft Excel validates record information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates record information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Negative Future Function Vulnerability - CVE-2010-3238

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3238.

Mitigating Factors for Negative Future Function Vulnerability - CVE-2010-3238

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Negative Future Function Vulnerability - CVE-2010-3238

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

Use Microsoft Office File Block policy to block the opening of Office 2003 and earlier documents from unknown or untrusted sources and locations

The following registry scripts can be used to set the File Block policy.

Note Modifying the Registry incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from incorrect modification of the Registry can be solved. Modify the Registry at your own risk.

For Office 2003

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]

"BinaryFiles"=dword:00000001

Note In order to use 'FileOpenBlock' with Microsoft Office 2003, all of the latest security updates for Microsoft Office 2003 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.

How to undo the workaround.

For Office 2003

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security\FileOpenBlock]

"BinaryFiles"=dword:00000000

Use the Microsoft Office Isolated Conversion Environment (MOICE) when opening files from unknown or untrusted sources

The Microsoft Office Isolated Conversion Environment (MOICE) helps protect Office 2003 installations by more securely opening Word, Excel, and PowerPoint binary format files.

To install MOICE, you must have Office 2003 or Office 2007 installed.

To install MOICE, you must also 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

Enable MOICE

Note See Microsoft Knowledge Base Article 935865 to use the automated Microsoft Fix it solution to enable or disable this workaround.

To manually enable MOICE, run the commands as specified in the following table. Running the commands will associate the Office application extensions with MOICE.
Command to enable MOICE to be the registered handler

For Word, run the following command from a command prompt:
ASSOC .doc=oice.word.document

For Excel, run the following commands from a command prompt:
ASSOC .XLS=oice.excel.sheet
ASSOC .XLT=oice.excel.template
ASSOC .XLA=oice.excel.addin

For PowerPoint, run the following commands from a command prompt:
ASSOC .PPT=oice.powerpoint.show
ASSOC .POT=oice.powerpoint.template
ASSOC .PPS=oice.powerpoint.slideshow

Note On Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, run the above commands 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 Microsoft Office 2007 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.

How to undo the workaround. Run the commands to disable MOICE as specified in the table below.
Command to disable MOICE as the registered handler

For Word, run the following command from a command prompt:
ASSOC .doc=Word.Document.8

For Excel, run the following commands from a command prompt:
ASSOC .xls=Excel.Sheet.8
ASSOC .xlt=Excel.Template
ASSOC .xla=Excel.Addin

For PowerPoint, run the following commands from a command prompt:
ASSOC .ppt=PowerPoint.Show.8
ASSOC .PPS=oice.powerpoint.slideshow
ASSOC .pps=PowerPoint.SlideShow.8

Note On Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, run the above commands from an elevated command prompt.

Do not open Microsoft Office files from untrusted sources

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 Negative Future Function Vulnerability - CVE-2010-3238

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?
When Microsoft Excel validates binary file format information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates binary file format information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Extra Out of Boundary Record Parsing Vulnerability - CVE-2010-3239

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3239.

Mitigating Factors for Extra Out of Boundary Record Parsing Vulnerability - CVE-2010-3239

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Extra Out of Boundary Record Parsing Vulnerability - CVE-2010-3239

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 Microsoft Office files from untrusted sources

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.
Top of sectionTop of section

FAQ for Extra Out of Boundary Record Parsing Vulnerability - CVE-2010-3239

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?
When Microsoft Excel validates record information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates record information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Real Time Data Array Record Vulnerability - CVE-2010-3240

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3240.

Mitigating Factors for Real Time Data Array Record Vulnerability - CVE-2010-3240

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Real Time Data Array Record Vulnerability - CVE-2010-3240

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

Use Microsoft Office File Block policy to block the opening of Office 2003 and earlier documents from unknown or untrusted sources and locations

The following registry scripts can be used to set the File Block policy.

Note Modifying the Registry incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from incorrect modification of the Registry can be solved. Modify the Registry at your own risk.

For Office 2007

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Excel\Security\FileOpenBlock]

"BinaryFiles"=dword:00000001

Note In order to use 'FileOpenBlock' with 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 2007.

How to undo the workaround.

For Office 2007

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Excel\Security\FileOpenBlock]

"BinaryFiles"=dword:00000000

Use the Microsoft Office Isolated Conversion Environment (MOICE) when opening files from unknown or untrusted sources

The Microsoft Office Isolated Conversion Environment (MOICE) helps protect Office 2003 installations by more securely opening Word, Excel, and PowerPoint binary format files.

To install MOICE, you must have Office 2003 or Office 2007 installed.

To install MOICE, you must also 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

Enable MOICE

Note See Microsoft Knowledge Base Article 935865 to use the automated Microsoft Fix it solution to enable or disable this workaround.

To manually enable MOICE, run the commands as specified in the following table. Running the commands will associate the Office application extensions with MOICE.
Command to enable MOICE to be the registered handler

For Word, run the following command from a command prompt:
ASSOC .doc=oice.word.document

For Excel, run the following commands from a command prompt:
ASSOC .XLS=oice.excel.sheet
ASSOC .XLT=oice.excel.template
ASSOC .XLA=oice.excel.addin

For PowerPoint, run the following commands from a command prompt:
ASSOC .PPT=oice.powerpoint.show
ASSOC .POT=oice.powerpoint.template
ASSOC .PPS=oice.powerpoint.slideshow

Note On Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, run the above commands 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 Microsoft Office 2007 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.

How to undo the workaround. Run the commands to disable MOICE as specified in the table below.
Command to disable MOICE as the registered handler

For Word, run the following command from a command prompt:
ASSOC .doc=Word.Document.8

For Excel, run the following commands from a command prompt:
ASSOC .xls=Excel.Sheet.8
ASSOC .xlt=Excel.Template
ASSOC .xla=Excel.Addin

For PowerPoint, run the following commands from a command prompt:
ASSOC .ppt=PowerPoint.Show.8
ASSOC .PPS=oice.powerpoint.slideshow
ASSOC .pps=PowerPoint.SlideShow.8

Note On Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, run the above commands from an elevated command prompt.

Do not open Microsoft Office files from untrusted sources

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 Real Time Data Array Record Vulnerability - CVE-2010-3240

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?
When Microsoft Excel validates record information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates record information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Out-of-Bounds Memory Write in Parsing Vulnerability - CVE-2010-3241

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3241.

Mitigating Factors for Out-of-Bounds Memory Write in Parsing Vulnerability - CVE-2010-3241

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
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Workarounds for Out-of-Bounds Memory Write in Parsing Vulnerability - CVE-2010-3241

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 Microsoft Office files from untrusted sources

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.
Top of sectionTop of section

FAQ for Out-of-Bounds Memory Write in Parsing Vulnerability - CVE-2010-3241

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?
When Microsoft Excel validates record information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates binary file format information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.
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Ghost Record Type Parsing Vulnerability - CVE-2010-3242

A remote code execution vulnerability exists in the way that Microsoft Excel handles specially crafted Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3242.

Mitigating Factors for Ghost Record Type Parsing Vulnerability - CVE-2010-3242

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.

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to convince users 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 Web site, and then convince them to open the specially crafted Excel file.
Top of sectionTop of section

Workarounds for Ghost Record Type Parsing Vulnerability - CVE-2010-3242

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 Microsoft Office files from untrusted sources

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.
Top of sectionTop of section

FAQ for Ghost Record Type Parsing Vulnerability - CVE-2010-3242

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?
When Microsoft Excel validates record information upon opening a specially crafted Excel file, a memory handling 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 run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability?
Exploitation of this vulnerability requires that a user open a specially crafted Excel file with an affected version of Microsoft 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 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, and then convince them to open the specially crafted Excel file.

What systems are primarily at risk from the vulnerability?
Systems where Microsoft Excel 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 addresses the vulnerability by modifying the way that Microsoft Excel validates record information.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.

Other Information
Acknowledgments

Microsoft thanks the following for working with us to help protect customers:

Alin Rad Pop of Secunia for reporting the Excel Record Parsing Integer Overflow Vulnerability (CVE-2010-3230)

Chaouki Bekrar of VUPEN Vulnerability Research Team for reporting the Excel Record Parsing Memory Corruption Vulnerability (CVE-2010-3231)

Omair for reporting the Excel File Format Parsing Vulnerability (CVE-2010-3232)

Carsten H. Eiram of Secunia for reporting the Lotus 1-2-3 Workbook Parsing Vulnerability (CVE-2010-3233)

Chaouki Bekrar of VUPEN Vulnerability Research Team for reporting the Formula Substream Memory Corruption Vulnerability (CVE-2010-3234)

Chaouki Bekrar of VUPEN Vulnerability Research Team for reporting the Formula Biff Record Vulnerability (CVE-2010-3235)

Chaouki Bekrar of VUPEN Vulnerability Research Team for reporting the Out Of Bounds Array Vulnerability (CVE-2010-3236)

Chaouki Bekrar of VUPEN Vulnerability Research Team for reporting the Merge Cell Record Pointer Vulnerability (CVE-2010-3237)

Chaouki Bekrar of VUPEN Vulnerability Research Team for reporting the Negative Future Function Vulnerability (CVE-2010-3238)

Chaouki Bekrar of VUPEN Vulnerability Research Team for reporting the Extra Out of Boundary Record Parsing Vulnerability (CVE-2010-3239)

Alin Rad Pop of Secunia for reporting the Extra Out of Boundary Record Parsing Vulnerability (CVE-2010-3239)

Chaouki Bekrar of VUPEN Vulnerability Research Team for reporting the Real Time Data Array Record Vulnerability (CVE-2010-3240)

Chaouki Bekrar of VUPEN Vulnerability Research Team for reporting the Out-of-Bounds Memory Write in Parsing Vulnerability (CVE-2010-3241)

Chaouki Bekrar of VUPEN Vulnerability Research Team for reporting the Ghost Record Type Parsing Vulnerability (CVE-2010-3242)

Carsten H. Eiram of Secunia for reporting the Ghost Record Type Parsing Vulnerability (CVE-2010-3242)

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 (October 12, 2010): Bulletin published.