Microsoft Security Bulletin MS07-049 - Important Vulnerability in Virtual PC and Virtual Server Could Allow Elevation of Privilege (937986)

Microsoft Security Bulletin MS07-049 - Important
Vulnerability in Virtual PC and Virtual Server Could Allow Elevation of Privilege (937986)
Published: August 14, 2007

Version: 1.0
General Information
Executive Summary

This important security update resolves one privately reported vulnerability. This is an elevation of privilege vulnerability. The vulnerability in Microsoft Virtual PC and Microsoft Virtual Server could allow a guest operating system user to run code on the host or another guest operating systems. Only guest operating system users who are granted administrative permissions to the guest operating system would be able to exploit this vulnerability. Guest operating system users not granted administrative permissions to the guest operating system would be unable to exploit this vulnerability.

This is an important security update for supported releases of Microsoft Virtual PC 2004, Microsoft Virtual Server 2005, Microsoft Virtual Server 2005 R2, Microsoft Virtual PC for Mac Version 6.1, and Microsoft Virtual PC for Mac Version 7. For more information, see the subsection, Affected and Non-Affected Software, in this section.

This security update addresses the vulnerability by improving interaction and initialization of components that communicate with the host operating system for virtual machines running under Microsoft Virtual PC and Microsoft Virtual Server. 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. Microsoft Knowledge Base Article 937986 documents the currently known issues that customers may experience when they install this security update. The article also documents recommended solutions for these issues.
Top of sectionTop of section
Affected and Non-Affected Software

The software listed here has 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
Affected Software Maximum Security Impact Aggregate Severity Rating Bulletins Replaced by This Update

Microsoft Virtual PC 2004

Elevation of Privilege

Important

None

Microsoft Virtual PC 2004 Service Pack 1

Elevation of Privilege

Important

None

Microsoft Virtual Server 2005 Standard Edition

Elevation of Privilege

Important

None

Microsoft Virtual Server 2005 Enterprise Edition

Elevation of Privilege

Important

None

Microsoft Virtual Server 2005 R2 Standard Edition

Elevation of Privilege

Important

None

Microsoft Virtual Server 2005 R2 Enterprise Edition

Elevation of Privilege

Important

None

Microsoft Virtual PC for Mac Version 6.1

Elevation of Privilege

Important

None

Microsoft Virtual PC for Mac Version 7

Elevation of Privilege

Important

None
Top of sectionTop of section

Non-Affected Software
Non-Affected Software

Microsoft Virtual PC 2007

Microsoft Virtual Server 2005 R2 Service Pack 1
Top of sectionTop of section

Frequently Asked Questions (FAQ) Related to This Security Update

What are the known issues that customers may experience when they install this security update?
Microsoft Knowledge Base Article 937986 documents the currently known issues that customers may experience when they install this security update. The article also documents recommended solutions for these issues.

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 has 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 the following Microsoft Support Lifecycle. For more information about the extended security update support period for these software releases, visit the Microsoft Product Support Services Web site.

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, 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.
Top of sectionTop of section
Vulnerability Information

Severity Ratings and Vulnerability Identifiers
Affected Software Virtual PC and Virtual Server Heap Overflow Vulnerability CVE-2007-0948 Aggregate Severity Rating

Microsoft Virtual PC 2004

Important

Elevation of Privilege

Important

Microsoft Virtual PC 2004 Service Pack 1

Important

Elevation of Privilege

Important

Microsoft Virtual Server 2005 Standard Edition

Important

Elevation of Privilege

Important

Microsoft Virtual Server 2005 Enterprise Edition

Important

Elevation of Privilege

Important

Microsoft Virtual Server 2005 R2 Standard Edition

Important

Elevation of Privilege

Important

Microsoft Virtual Server 2005 R2 Enterprise Edition

Important

Elevation of Privilege

Important

Microsoft Virtual PC for Mac Version 6.1

Important

Elevation of Privilege

Important

Microsoft Virtual PC for Mac Version 7

Important

Elevation of Privilege

Important
Top of sectionTop of section

Virtual PC and Virtual Server Heap Overflow Vulnerability - CVE-2007-0948

An elevation of privilege vulnerability exists in Microsoft Virtual PC and Microsoft Virtual Server that could allow a user with administrator permissions to the guest operating system to run code on the host operating system or other guest operating systems. An attacker with administrator permissions to the guest operating system, could exploit the vulnerability by running specially crafted code on the guest operating system. This could result in a heap overflow on the host or other guest operating systems. An attacker who successfully exploited this vulnerability could take complete control of an affected system.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2007-0948.

Mitigating Factors for Virtual PC and Virtual Server Heap Overflow Vulnerability - CVE-2007-0948

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

An attacker must have administrator permissions to the guest operating system to exploit this vulnerability. Guest operating system logins not granted administrative permissions to the guest operating system are unable to exploit this vulnerability.
•

Microsoft Virtual PC 2007 is not vulnerable to this issue. You can download the full version of Microsoft Virtual PC 2007 on the Microsoft Download Center.
•

Microsoft Virtual Server 2005 R2 SP1 is not vulnerable to this issue. You can download the full version of Microsoft Virtual Server 2005 R2 SP1 on the Microsoft Download Center.
Top of sectionTop of section

Workarounds for Virtual PC and Virtual Server Heap Overflow Vulnerability - CVE-2007-0948

Microsoft has not identified any workarounds for this vulnerability.
Top of sectionTop of section

FAQ for Virtual PC and Virtual Server Heap Overflow Vulnerability - CVE-2007-0948

What is the scope of the vulnerability?
An elevation of privilege vulnerability exists in Microsoft Virtual PC and Microsoft Virtual Server that could allow a user with administrator permissions to the guest operating system to run code on the host operating system or other guest operating systems. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs or view, change, or delete data.

What causes the vulnerability?
Interaction and initialization of components that communicate with the host operating system are not performed correctly in Microsoft Virtual PC and Microsoft Virtual Server.

What might an attacker use the vulnerability to do?
An attacker with administrator permissions to the guest operating who successfully exploited this vulnerability could take complete control of an affected system. The attacker could then gain access to host or other guest operating systems which could result in a heap overflow on the host or other guest operating systems.

How could an attacker exploit the vulnerability?
An attacker with administrator permissions to the guest operating system could run specially crafted code to exploit this vulnerability. An attacker must have administrator permissions to the guest operating system to exploit this vulnerability.

What systems are primarily at risk from the vulnerability?
Any systems where Microsoft Virtual PC or Microsoft Virtual Server is used, such as workstations or terminal servers, are at risk from this vulnerability. This vulnerability requires that an attacker have administrator permissions to the guest operating system to exploit this vulnerability. Guest operating system logins not granted administrative permissions on the guest operating system are unable to exploit this vulnerability.

What does the update do?
The update removes the vulnerability in Microsoft Virtual PC and Microsoft Virtual Server by modifying interaction and initialization of components that communicate with the host operating system.

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.

Other Information
Acknowledgments

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

Rafal Wojtczuk of McAfee Avert Labs for working with Microsoft on the Vulnerability in Virtual PC and Virtual Server Could Allow Elevation of Privilege Vulnerability – (CVE-2007-0948).
Top of sectionTop of section
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 (August 14, 2007): Bulletin published.