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Support for Windows Vista Service Pack 1 (SP1) ends on July 12, 2011. To continue receiving security updates for Windows, make sure you're running Windows Vista with Service Pack 2 (SP2). For more information, refer to this Microsoft web page: Support is ending for some versions of Windows.

Symptoms

Consider the following scenario:

  • The following policies are enabled on a domain controller that is running Windows Server 2003 in a domain:

    • Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\Microsoft network server: Digitally sign communications (always)

    • Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\Microsoft network server: Digitally sign communications (if client agrees)

  • The following policies are enabled on a member computer that is running Windows Vista Service Pack 1 or Windows Server 2008 in the same domain:

    • Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\Microsoft network client: Digitally sign communications (always)

    • Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\Microsoft network client: Digitally sign communications (If server agrees)

In this scenario, Group Policy settings are not applied on the member computer. Additionally, the following event is logged in the System log on the member computer:Note This problem occurs only on member computers that are running Windows Server 2008 or Windows Vista Service Pack 1 (SP1). It does not occur on member computers that are running Windows Server 2003, Windows XP, or the release version of Windows Vista.

Cause

When a Server Message Block (SMB) version 1 client establishes a non-guest session or a non-anonymous session with a server, the client enables security signatures for the server. Later sessions then inherit the security signature sequence that is already established.

To improve security, Windows Server 2008 and Windows Vista SP1 prevent server authenticated connections from being maliciously downgraded to a guest session or to an anonymous session. However, this improved security does not address the scenario that is described in the "Symptoms" section.

Resolution

Windows Server 2008 hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=supportNote The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

There are no prerequisites for installing this hotfix.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2008, x86-based versions

File name

File version

File size

Date

Time

Platform

Mrxsmb10.sys

6.0.6001.22156

211,968

12-Apr-2008

00:43

x86

Windows Server 2008, Itanium-based versions

File name

File version

File size

Date

Time

Platform

Mrxsmb10.sys

6.0.6001.22156

655,360

12-Apr-2008

00:54

IA-64

Windows Server 2008, x64-based versions

File name

File version

File size

Date

Time

Platform

Mrxsmb10.sys

6.0.6001.22156

272,384

12-Apr-2008

01:17

x64

Windows Vista Service Pack 1 hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=supportNote The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must have Windows Vista SP1 installed.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista with Service Pack 1, x86-based versions

File name

File version

File size

Date

Time

Platform

Mrxsmb10.sys

6.0.6001.22156

211,968

12-Apr-2008

00:43

x86

Windows Vista with Service Pack 1, Itanium-based versions

File name

File version

File size

Date

Time

Platform

Mrxsmb10.sys

6.0.6001.22156

655,360

12-Apr-2008

00:54

IA-64

Windows Vista with Service Pack 1, x64-based versions

File name

File version

File size

Date

Time

Platform

Mrxsmb10.sys

6.0.6001.22156

272,384

12-Apr-2008

01:17

x64

Workaround

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 How to back up and restore the registry in WindowsTo work around this problem, use one of the following methods.

Method 1

Disable the following policy on the member computers that are running Windows Server 2008 or Windows Vista SP1:

Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\Microsoft network client: Digitally sign communications (always)

Method 2

On the member computers that are running Windows Server 2008 or Windows Vista SP1, follow these steps:

  1. Click Start, type regedit in the Start Search box, and then press ENTER.

  2. Locate the RequireSecuritySignature registry entry under the following registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanworkstation\parameters

  3. Right-click RequireSecuritySignature, and then click Modify.

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

  5. Exit Registry Editor.

Method 3

On the member computers that are running Windows Server 2008 or Windows Vista Service Pack 1, follow these steps:

  1. Click Start, type regedit in the Start Search box, and then press ENTER.

  2. Locate the AllowGuestAuthWhenSigningRequired registry entry under the following registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanworkstation\parameters

  3. Right-click AllowGuestAuthWhenSigningRequired, and then click Modify.

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

  5. Exit Registry Editor.

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

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