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SMB/CIFS sessions leak in Windows Vista, in Windows Server 2008, in Windows 7 and in Windows Server 2008 R2


View products that this article applies to.

Symptoms

When you run an application or service that accesses a remote Server Message Block (SMB)/Common Internet File System (CIFS) server, the number of CIFS sessions keeps increasing.

This issue occurs on a computer that is running one of the following operating systems:
  • Windows Vista
  • Windows Server 2008
  • Windows 7
  • Windows Server 2008 R2
When the resources are exhausted, the remote SMB/CIFS server does not respond to client requests.

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Cause

This issue occurs because the Distributed File System (DFS) Namespace Client Driver (Dfsc.sys) does not release CIFS sessions correctly if a pre-existing server connection exists.

For example, a named pipe connection to the file server is a pre-existing server connection.

When another connection maps and unmaps a drive, or when another connection opens and closes the network location, this issue occurs if a named pipe connection exists.

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Resolution

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 the problem described in this article. 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: Note 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 be running one of the following operating systems:
  • Windows Vista Service Pack 2 (SP2)
  • Windows Server 2008 Service Pack 2 (SP2)
  • Windows 7
  • Windows 7 Service Pack 1 (SP1)
  • Windows Server 2008 R2
  • Windows Server 2008 R2 Service Pack 1 (SP1)
For more information about how to obtain a Windows Vista service pack, click the following article number to view the article in the Microsoft Knowledge Base:

935791 How to obtain the latest Windows Vista service pack

For more information about how to obtain a Windows Server 2008 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

968849 How to obtain the latest service pack for Windows Server 2008

For more information about how to obtain a Windows 7 or a Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

976932 Information about Service Pack 1 for Windows 7 and for Windows Server 2008 R2

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

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 global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.
Windows Vista and Windows Server 2008 file information notes
Important Windows Vista hotfixes and Windows Server 2008 hotfixes are included in the same packages. However, only "Windows Vista" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows Vista" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.
  • The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.
    VersionProductSR_LevelService branch
    6.0.600
    2.
    22xxx
    Windows Vista and Windows Server 2008SP2LDR
  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 and for Windows Vista" section. MUM files and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
For all supported x86-based versions of Windows Server 2008 and of Windows Vista
File nameFile versionFile sizeDateTimePlatform
Dfsc.sys6.0.6002.2262575,26414-Apr-201114:36x86
For all supported x64-based versions of Windows Server 2008 and of Windows Vista
File nameFile versionFile sizeDateTimePlatform
Dfsc.sys6.0.6002.2262597,79214-Apr-201114:57x64
For all supported IA-64–based versions of Windows Server 2008
File nameFile versionFile sizeDateTimePlatform
Dfsc.sys6.0.6002.22625238,59214-Apr-201114:49IA-64
Windows 7 and Windows Server 2008 R2 file information notes
Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.
  • The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.
    VersionProductSR_LevelService branch
    6.1.760
    0.
    20xxx
    Windows 7 and Windows Server 2008 R2RTMLDR
    6.1.760
    1.
    21xxx
    Windows 7 and Windows Server 2008 R2SP1LDR
  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 R2 and for Windows 7" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
For all supported x86-based versions of Windows 7
File nameFile versionFile sizeDateTimePlatform
Dfsc.sys6.1.7600.2098678,33615-Jun-201106:45x86
Dfsc.sys6.1.7601.2174778,33615-Jun-201106:38x86
For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Dfsc.sys6.1.7600.20986102,40015-Jun-201107:08x64
Dfsc.sys6.1.7601.21747102,40015-Jun-201106:56x64
For all supported IA-64-based versions of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform
Dfsc.sys6.1.7600.20986247,29615-Jun-201106:29IA-64
Dfsc.sys6.1.7601.21747247,29615-Jun-201106:16IA-64

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Status

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

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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

Additional file information

Additional file information for Windows Vista and for Windows Server 2008

Additional files for all supported x86-based versions of Windows Vista and of Windows Server 2008
File nameUpdate.mum
File versionNot applicable
File size3,078
Date (UTC)14-Apr-2011
Time (UTC)19:19
PlatformNot applicable
File nameX86_606e964c74b13aae543b35557c3795b1_31bf3856ad364e35_6.0.6002.22625_none_a8083a3ea80b4c56.manifest
File versionNot applicable
File size697
Date (UTC)14-Apr-2011
Time (UTC)19:19
PlatformNot applicable
File nameX86_microsoft-windows-dfsclient_31bf3856ad364e35_6.0.6002.22625_none_89f9ad5afc6b7999.manifest
File versionNot applicable
File size10,277
Date (UTC)14-Apr-2011
Time (UTC)17:07
PlatformNot applicable
Additional files for all supported x64-based versions of Windows Vista and of Windows Server 2008
File nameAmd64_0a5240e86011fb2c0c621eac8545ada9_31bf3856ad364e35_6.0.6002.22625_none_5be6b758050bc52c.manifest
File versionNot applicable
File size701
Date (UTC)14-Apr-2011
Time (UTC)19:19
PlatformNot applicable
File nameAmd64_microsoft-windows-dfsclient_31bf3856ad364e35_6.0.6002.22625_none_e61848deb4c8eacf.manifest
File versionNot applicable
File size10,538
Date (UTC)14-Apr-2011
Time (UTC)17:13
PlatformNot applicable
File nameUpdate.mum
File versionNot applicable
File size3,102
Date (UTC)14-Apr-2011
Time (UTC)19:19
PlatformNot applicable
Additional files for all supported IA-64–based versions of Windows Server 2008
File nameIa64_2eb723c922bed3d306faaf31e0236901_31bf3856ad364e35_6.0.6002.22625_none_9269d3a140b135c6.manifest
File versionNot applicable
File size699
Date (UTC)14-Apr-2011
Time (UTC)19:19
PlatformNot applicable
File nameIa64_microsoft-windows-dfsclient_31bf3856ad364e35_6.0.6002.22625_none_89fb5150fc698295.manifest
File versionNot applicable
File size10,532
Date (UTC)14-Apr-2011
Time (UTC)16:59
PlatformNot applicable
File nameUpdate.mum
File versionNot applicable
File size2,255
Date (UTC)14-Apr-2011
Time (UTC)19:19
PlatformNot applicable

Additional file information for Windows 7 and for Windows Server 2008 R2

Additional files for all supported x86-based versions of Windows 7
File nameUpdate.mum
File versionNot Applicable
File size2,773
Date (UTC)15-Jun-2011
Time (UTC)13:45
PlatformNot Applicable
File nameX86_microsoft-windows-dfsclient_31bf3856ad364e35_6.1.7600.20986_none_87fb2a94608c2533.manifest
File versionNot Applicable
File size8,646
Date (UTC)15-Jun-2011
Time (UTC)09:17
PlatformNot Applicable
File nameX86_microsoft-windows-dfsclient_31bf3856ad364e35_6.1.7601.21747_none_8a0dc7945d913ab2.manifest
File versionNot Applicable
File size8,646
Date (UTC)15-Jun-2011
Time (UTC)09:16
PlatformNot Applicable
Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
File nameAmd64_microsoft-windows-dfsclient_31bf3856ad364e35_6.1.7600.20986_none_e419c61818e99669.manifest
File versionNot Applicable
File size8,648
Date (UTC)15-Jun-2011
Time (UTC)10:21
PlatformNot Applicable
File nameAmd64_microsoft-windows-dfsclient_31bf3856ad364e35_6.1.7601.21747_none_e62c631815eeabe8.manifest
File versionNot Applicable
File size8,648
Date (UTC)15-Jun-2011
Time (UTC)10:16
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size3,215
Date (UTC)15-Jun-2011
Time (UTC)13:46
PlatformNot Applicable
Additional files for all supported IA-64-based versions of Windows Server 2008 R2
File nameIa64_microsoft-windows-dfsclient_31bf3856ad364e35_6.1.7600.20986_none_87fcce8a608a2e2f.manifest
File versionNot Applicable
File size8,647
Date (UTC)15-Jun-2011
Time (UTC)10:16
PlatformNot Applicable
File nameIa64_microsoft-windows-dfsclient_31bf3856ad364e35_6.1.7601.21747_none_8a0f6b8a5d8f43ae.manifest
File versionNot Applicable
File size8,647
Date (UTC)15-Jun-2011
Time (UTC)10:05
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size2,168
Date (UTC)15-Jun-2011
Time (UTC)13:45
PlatformNot Applicable

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Keywords: kb, kbautohotfix, kbqfe, kbhotfixserver, kbfix, kbsurveynew, kbexpertiseinter, kbexpertiseadvanced

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Article Info
Article ID : 2537589
Revision : 1
Created on : 1/7/2017
Published on : 12/27/2012
Exists online : False
Views : 337