Microsoft Security Bulletin MS08-071 – Critical Vulnerabilities in GDI Could Allow Remote Code Execution (956802)

Microsoft Security Bulletin MS08-071 – Critical
Vulnerabilities in GDI Could Allow Remote Code Execution (956802)
Published: December 9, 2008

Version: 1.0
General Information
Executive Summary

This security update resolves two privately reported vulnerabilities in GDI. Exploitation of either of these vulnerabilities could allow remote code execution if a user opens a specially crafted WMF image file. An attacker who successfully exploited these vulnerabilities could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

This security update is rated Critical for all supported editions of Microsoft Windows 2000, Windows XP, Windows Server 2003, Windows Vista, and Windows Server 2008. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerabilities by modifying the way GDI validates file size parameters and performs integer calculations to prevent overflow conditions. For more information about the vulnerabilities, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

Recommendation. Microsoft recommends that customers apply the update immediately.

Known Issues. None
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Affected and Non-Affected Software

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

Affected Software
Operating System Maximum Security Impact Aggregate Severity Rating Bulletins Replaced by this Update

Microsoft Windows 2000 Service Pack 4

Remote Code Execution

Critical

MS08-021

Windows XP Service Pack 2

Remote Code Execution

Critical

MS08-021

Windows XP Service Pack 3

Remote Code Execution

Critical

None

Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2

Remote Code Execution

Critical

MS08-021

Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2

Remote Code Execution

Critical

MS08-021

Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service Pack 2

Remote Code Execution

Critical

MS08-021

Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems

Remote Code Execution

Critical

MS08-021

Windows Vista and Windows Vista Service Pack 1

Remote Code Execution

Critical

MS08-021

Windows Vista x64 Edition and Windows Vista x64 Edition Service Pack 1

Remote Code Execution

Critical

MS08-021

Windows Server 2008 for 32-bit Systems*

Remote Code Execution

Critical

MS08-021

Windows Server 2008 for x64-based Systems*

Remote Code Execution

Critical

MS08-021

Windows Server 2008 for Itanium-based Systems

Remote Code Execution

Critical

MS08-021

*Windows Server 2008 server core installation affected. For supported editions of Windows Server 2008, this update applies, with the same severity rating, whether or not Windows Server 2008 was installed using the Server Core installation option. For more information on this installation option, see Server Core. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008; see Compare Server Core Installation Options.
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Frequently Asked Questions (FAQ) Related to This Security Update

Where are the file information details?
The file information details can be found in Microsoft Knowledge Base Article 956802.

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.

I am using an older release of the software discussed in this security bulletin. What should I do?
The affected software listed in this bulletin have been tested to determine which releases are affected. Other releases are past their support life cycle. To determine the support life cycle for your software release, visit Microsoft Support Lifecycle.

It should be a priority for customers who have older releases of the software to migrate to supported releases to prevent potential exposure to vulnerabilities. For more information about the Windows Product Lifecycle, visit Microsoft Support Lifecycle. For more information about the extended security update support period for these software versions or editions, visit Microsoft Product Support Services.

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

Severity Ratings and Vulnerability Identifiers
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software GDI Integer Overflow Vulnerability - CVE-2008-2249 GDI Heap Overflow Vulnerability - CVE-2008-3465 Aggregate Severity Rating

Microsoft Windows 2000 Service Pack 4

Critical
Remote Code Execution

Moderate
Denial of Service

Critical

Windows XP Service Pack 2 and Windows XP Service Pack 3

Critical
Remote Code Execution

Moderate
Denial of Service

Critical

Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2

Critical
Remote Code Execution

Moderate
Denial of Service

Critical

Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2

Critical
Remote Code Execution

Moderate
Denial of Service

Critical

Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service Pack 2

Critical
Remote Code Execution

Moderate
Denial of Service

Critical

Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems

Critical
Remote Code Execution

Moderate
Denial of Service

Critical

Windows Vista and Windows Vista Service Pack 1

Critical
Remote Code Execution

Low
Denial of Service

Critical

Windows Vista x64 Edition and Windows Vista x64 Edition Service Pack 1

Critical
Remote Code Execution

Low
Denial of Service

Critical

Windows Server 2008 for 32-bit Systems*

Critical
Remote Code Execution

Low
Denial of Service

Critical

Windows Server 2008 for x64-based Systems*

Critical
Remote Code Execution

Low
Denial of Service

Critical

Windows Server 2008 for Itanium-based Systems

Critical
Remote Code Execution

Low
Denial of Service

Critical

*Windows Server 2008 server core installation affected. For supported editions of Windows Server 2008, this update applies, with the same severity rating, whether or not Windows Server 2008 was installed using the Server Core installation option. For more information on this installation option, see Server Core. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008; see Compare Server Core Installation Options.
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GDI Integer Overflow Vulnerability - CVE-2008-2249

A remote code execution vulnerability exists in the way that GDI handles integer calculations. The vulnerability could allow remote code execution if a user opens a specially crafted WMF image file. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2008-2249.

Mitigating Factors for GDI Integer Overflow Vulnerability - CVE-2008-2249

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:
•

An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
•

In a Web-based attack scenario, an attacker 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.
•

Users who have installed and are using the Office Document Open Confirmation Tool for Office 2000 will be prompted with Open, Save, or Cancel before opening a document. The features of the Office Document Open Confirmation Tool are incorporated in Office XP and later editions of Office.
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Workarounds for GDI Integer Overflow Vulnerability - CVE-2008-2249

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:
•

Turn off metafile processing by modifying the registry
Customers who have applied MS07-017 or customers using Windows Vista or Windows Server 2008 can disable metafile processing by modifying the registry. This setting will help protect the affected system from attempts to exploit this vulnerability.

To modify the key, follow these steps:

Note Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or view the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe.

Click Start, click Run, type Regedit in the Open box, and then click OK.

Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\GRE_Initialize

On the Edit menu, point to New, and then click DWORD.

Type DisableMetaFiles, and then press ENTER.

On the Edit menu, click Modify to modify the DisableMetaFiles registry entry.

In the Value data box, type 1, and then click OK.

Exit Registry Editor.

Reboot the computer.

Impact of workaround. Turning off processing of metafiles may cause the appearance of the output from software or system components to decrease in quality. Turning off processing of metafiles may also cause software or system components to fail completely. This workaround has been identified to have a potentially significant functionality impact and should be evaluated and tested carefully to determine its applicability.

Examples include the following:
•

You cannot print on the computer.
•

Some applications on the computer may be unable to display Clipart.
•

Some scenarios that involve OLE rendering may break. This most often occurs when the object server is not active.

For more information on this setting read Microsoft Knowledge Base Article 941835.

How to undo the workaround.

Click Start, click Run, type Regedit in the Open box, and then click OK.

Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\GRE_Initialize

On the Edit menu, click Modify to modify the DisableMetaFiles registry entry.

In the Value data box, type 0, and then click OK.

Exit Registry Editor.

Reboot the computer.

You may have to restart your computer for this change to take effect.
•

Read E-mail in Plain Text

To help protect yourself from the e-mail attack vector, read e-mail messages in plain text format.

Microsoft Outlook 2002 users who have applied Office XP Service Pack 1 or a later version and Microsoft Outlook Express 6 users who have applied Internet Explorer 6 Service Pack 1 or a later version can enable this setting and view e-mail messages that are not digitally signed or e-mail messages that are not encrypted in plain text only.

Digitally signed e-mail messages or encrypted e-mail messages are not affected by the setting and may be read in their original formats. For more information about how to enable this setting in Outlook 2002, see Microsoft Knowledge Base Article 307594.

For information about this setting in Outlook Express 6, see Microsoft Knowledge Base Article 291387.

Impact of workaround: E-mail messages that are viewed in plain text format will not contain pictures, specialized fonts, animations, or other rich content. Additionally:
•

The changes are applied to the preview pane and to open messages.
•

Pictures become attachments so that they are not lost.
•

Because the message is still in Rich Text or HTML format in the store, the object model (custom code solutions) may behave unexpectedly.
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FAQ for GDI Integer Overflow Vulnerability - CVE-2008-2249

What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

What causes the vulnerability?
The vulnerability is caused by a buffer overflow when GDI improperly processes a malformed header in a specially crafted WMF image file.

What is GDI?
The Microsoft Windows graphics device interface (GDI) enables applications to use graphics and formatted text on both the video display and the printer. Windows-based applications do not access the graphics hardware directly. Instead, GDI interacts with device drivers on behalf of applications. For more information about GDI, visit the Windows GDI Start Page.

What is the Windows Metafile (WMF) image format?
The WMF image format is a 16-bit metafile format that can contain both vector information and bitmap information. It is optimized for the Windows operating system.

For more information about image types and formats, see Microsoft Knowledge Base Article 320314. Additional information about these file formats is also available at the MSDN Library Web Site.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
This vulnerability requires that a user view a specially crafted image file.

In an e-mail attack scenario, an attacker could exploit the vulnerability by sending an e-mail with a specially-crafted WMF image file embedded in it to the user and convincing the user to view or preview the email. An attacker could also embed a specially-crafted WMF image file in an Office document and convince the user to open the file.

In a Web-based attack scenario, an attacker would have to host a Web site that contains a WMF image file that is used to attempt to exploit this vulnerability. In addition, compromised Web sites and Web sites that accept or host user-provided content could contain specially crafted content that could exploit this vulnerability. An attacker would have no way to force users to visit a specially crafted Web site. Instead, an attacker would have to convince them to visit the Web site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes them to the attacker's site.

What systems are primarily at risk from the vulnerability?
Workstations and terminal servers are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.

What does the update do?
The update addresses the vulnerability by modifying the way GDI performs integer calculations to prevent an overflow condition.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued. This security bulletin addresses the privately disclosed vulnerability as well as additional issues discovered through internal investigations.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.
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GDI Heap Overflow Vulnerability - CVE-2008-3465

A remote code execution vulnerability exists in the way that GDI handles file size parameters in WMF files. The vulnerability could allow remote code execution if a third-party application uses a specific Microsoft API to copy a specially crafted WMF image file. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2008-3465.

Mitigating Factors for GDI Heap Overflow Vulnerability - CVE-2008-3465

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:
•

An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
Top of sectionTop of section

Workarounds for GDI Heap Overflow Vulnerability - CVE-2008-3465

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:
•

Turn off metafile processing by modifying the registry
Customers who have applied MS07-017 or customers using Windows Vista or Windows Server 2008 can disable metafile processing by modifying the registry. This setting will help protect the affected system from attempts to exploit this vulnerability.

To modify the key, follow these steps:

Note Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or view the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe.

Click Start, click Run, type Regedit in the Open box, and then click OK.

Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\GRE_Initialize

On the Edit menu, point to New, and then click DWORD.

Type DisableMetaFiles, and then press ENTER.

On the Edit menu, click Modify to modify the DisableMetaFiles registry entry.

In the Value data box, type 1, and then click OK.

Exit Registry Editor.

Reboot the computer.

Impact of workaround. Turning off processing of metafiles may cause the appearance of the output from software or system components to decrease in quality. Turning off processing of metafiles may also cause software or system components to fail completely. This workaround has been identified to have a potentially significant functionality impact and should be evaluated and tested carefully to determine its applicability.

Examples include the following:
•

You cannot print on the computer.
•

Some applications on the computer may be unable to display Clipart.
•

Some scenarios that involve OLE rendering may break. This most often occurs when the object server is not active.

For more information on this setting read Microsoft Knowledge Base Article 941835.

How to undo the workaround.

Click Start, click Run, type Regedit in the Open box, and then click OK.

Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\GRE_Initialize

On the Edit menu, click Modify to modify the DisableMetaFiles registry entry.

In the Value data box, type 0, and then click OK.

Exit Registry Editor.

Reboot the computer.

You may have to restart your computer for this change to take effect.
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FAQ for GDI Heap Overflow Vulnerability - CVE-2008-3465

What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

What causes the vulnerability?
The vulnerability is caused by a heap overflow when GDI improperly processes a malformed file size parameter in a specially crafted WMF image file.

What is GDI?
The Microsoft Windows graphics device interface (GDI) enables applications to use graphics and formatted text on both the video display and the printer. Windows-based applications do not access the graphics hardware directly. Instead, GDI interacts with device drivers on behalf of applications. For more information about GDI, visit the Windows GDI Start Page.

What is the Windows Metafile (WMF) image format?
The WMF image format is a 16-bit metafile format that can contain both vector information and bitmap information. It is optimized for the Windows operating system.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

On Windows Vista and Windows Server 2008, an attacker who successfully exploited this vulnerability could cause the affected application to become non-responsive. The application would need to be restarted to restore functionality.

How could an attacker exploit the vulnerability?
This vulnerability requires a third-party application make a copy of a WMF file through this API. Depending on the behavior of the third-party application, this could lead to remote code execution in the context of the logged on user.

We are not currently aware of any remote avenues for accessing this vulnerability using Microsoft products.

How do I determine if a third party application is affected?
Users are encouraged to contact their third-party software vendors whose products process or potentially copy WMF files to determine if they are affected.

What systems are primarily at risk from the vulnerability?
All currently supported Windows systems are at risk.

What does the update do?
The update addresses the vulnerability by modifying the way GDI handles file size parameters to prevent buffer overflow conditions.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued. This security bulletin addresses the privately disclosed vulnerability as well as additional issues discovered through internal investigations.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.

Other Information
Acknowledgments

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

Jun Mao of VeriSign iDefense Labs for reporting the GDI Integer Overflow Vulnerability (CVE-2008-2249)
•

Juan Caballero, working with the Bitblaze group at Carnegie Mellon University and UC Berkeley, for reporting the GDI Heap Overflow Vulnerability (CVE-2008-3465)
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Microsoft Active Protections Program (MAPP)

To improve security protections for customers, Microsoft provides vulnerability information to major security software providers in advance of each monthly security update release. Security software providers can then use this vulnerability information to provide updated protections to customers via their security software or devices, such as antivirus, network-based intrusion detection systems, or host-based intrusion prevention systems. To determine whether active protections are available from security software providers, please visit the active protections Web sites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.

Support
•

Customers in the U.S. and Canada can receive technical support from Microsoft Product Support Services at 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates.
•

International customers can receive support from their local Microsoft subsidiaries. There is no charge for support that is associated with security updates. For more information about how to contact Microsoft for support issues, visit the International Support Web site.

Disclaimer

The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Revisions
•

V1.0 (December 9, 2008): Bulletin published.