Microsoft Security Bulletin MS07-066 – Important Vulnerability in Windows Kernel Could Allow Elevation of Privilege (943078)

Microsoft Security Bulletin MS07-066 – Important
Vulnerability in Windows Kernel Could Allow Elevation of Privilege (943078)
Published: December 11, 2007

Version: 1.0
General Information
Executive Summary

This important security update resolves a privately reported vulnerability in the Windows kernel. 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 administrative rights.

This is an important security update for supported editions of Windows Vista. For more information, see the subsection, Affected and Non-Affected Software, in this section.

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 at the earliest opportunity.

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

Windows Vista

Elevation of Privilege

Important

None

Windows Vista x64 Edition

Elevation of Privilege

Important

None

Non-Affected Software
Operating System

Microsoft Windows 2000 Service Pack 4

Windows XP Service Pack 2

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

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

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

Windows Server 2003 x64 Edition and Windows Server x64 Edition Service Pack 2
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Frequently Asked Questions (FAQ) Related to This Security Update

I am using an older version 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 versions or editions are affected. Other versions or editions are past their support life cycle. To determine the support life cycle for your software version or edition, visit Microsoft Support Lifecycle.

It should be a priority for customers who have older versions or editions of the software to migrate to supported versions or editions 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 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 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 Windows Kernel Vulnerability - CVE-2007-5350 Aggregate Severity Rating

Windows Vista

Important

Elevation of Privilege

Important

Windows Vista x64 Edition

Important

Elevation of Privilege

Important
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Windows Kernel Vulnerability - CVE-2007-5350

An elevation of privilege vulnerability exists in the way that the Windows kernel processes certain access requests. This vulnerability could allow an attacker to run code and to take complete control of the system. An attacker could then install programs; view, change, or delete data; or create new accounts with full administrative 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.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2007-5350.

Mitigating Factors for Windows Kernel Vulnerability - CVE-2007-5350

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 must have valid logon credentials and be able to log on locally to exploit this vulnerability. The vulnerability could not be exploited remotely or by anonymous users.
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Workarounds for Windows Kernel Vulnerability - CVE-2007-5350

Microsoft has not identified any workarounds for this vulnerability.
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FAQ for Windows Kernel Vulnerability - CVE-2007-5350

What is the scope of the vulnerability?
This is an elevation of privilege vulnerability. An attacker who successfully exploited this vulnerability could take complete control of an affected system, including installing programs; viewing, changing, or deleting data; or creating new accounts that have full privileges.

What causes the vulnerability?
Windows Advanced Local Procedure Call (ALPC) improperly validates certain conditions in legacy reply paths.

What is the kernel?
The kernel is the core of the operating system and it provides basic services for all other parts of the operating system.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could take complete control of an affected system, including installing programs; viewing, changing, or deleting data; or creating new accounts that have full privileges.

How could an attacker exploit the vulnerability?
To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take complete control over the affected system.

What systems are primarily at risk from the vulnerability?
Systems that are running Windows Vista are the systems that are primarily at risk.

What does the update do?
The update removes the vulnerability by modifying the way that the Windows kernel validates certain conditions in legacy reply paths.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received 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:
•

Thomas Garnier of SkyRecon for reporting the Windows Kernel Vulnerability (CVE-2007-5350).

Support
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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.
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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 11, 2007) Bulletin published.