Microsoft KB Archive/911647

= Applications that use Lightweight Directory Access Protocol (LDAP) over Secure Sockets Layer (SSL) do not perform revocation checking of the server certificate in Windows Server 2003 with Service Pack 1 =

Article ID: 911647

Article Last Modified on 10/11/2007

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APPLIES TO

 Microsoft Windows Server 2003 SP1, when used with:  Microsoft Windows Server 2003, Standard Edition (32-bit x86)

 Microsoft Windows Server 2003, Enterprise Edition

 Microsoft Windows Server 2003, Standard x64 Edition

 Microsoft Windows Server 2003, Enterprise x64 Edition</li></ul>

 Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems</li></ul> </li></ul>

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SYMPTOMS
You have certain applications that use the Windows Lightweight Directory Access Protocol (LDAP) APIs to access an LDAP directory over Secure Sockets Layer (SSL) on a Microsoft Windows Server 2003 Service Pack 1 (SP1)-based computer. However, these applications do not perform revocation checking of the certificate that is issued to the LDAP server.

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CAUSE
This problem occurs because of the following reasons.

In a Windows operating system, Microsoft Security Channel (SChannel) implements SSL and Transport Layer Security (TLS). By default, SChannel does not perform revocation checking of server authentication certificates. However, developers can modify this behavior by setting the appropriate SChannel flags before it calls into the component.

Additionally, the Wldap32.dll file implements the LDAP API in Windows. Developers can use the Wldap32.dll file calls to connect to a directory server over SSL or over TLS. The Wldap32.dll file depends on SChannel to help provide security for these connections. When the Wldap32.dll file calls into SChannel, the Wldap32.dll file does not modify the default behavior of SChannel authentication.

Therefore, when you use the Wldap32.dll file to connect to a directory server over SSL or TLS, the client computer does not perform revocation checking of the server authentication certificate.

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Service pack information
To resolve this problem, obtain the latest service pack for Windows Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

889100 How to obtain the latest service pack for Windows Server 2003

Prerequisites
You must have Windows Server 2003 SP1 installed to apply this hotfix.

Restart requirement
You must restart your computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace any other hotfixes.

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 2003 with SP1, Itanium-based versions
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STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section. This problem was first corrected in Windows Server 2003 Service Pack 2.

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MORE INFORMATION
After you apply this hotfix, a code change occurs in the Wldap32.dll file. This code change lets developers modify how the Wldap32.dll file uses SChannel. Additionally, there is a new LDAP session option that lets developers set the SChannel flags.

The new LDAP session option is as follows: define LDAP_OPT_SCH_FLAGS 0x43 For more information about how to set LDAP session options, visit the following Microsoft Developer Network (MSDN) Web site:

http://msdn2.microsoft.com/en-us/library/aa367019.aspx

If the LDAP_OPT_SCH_FLAGS option is not set, the default SChannel flags that are used by the Wldap32.dll file are as follows: (SCH_CRED_USE_DEFAULT_CREDS | SCH_CRED_AUTO_CRED_VALIDATION) For more information about SChannel flags, visit the following Microsoft MSDN Web site:

http://msdn2.microsoft.com/ru-ru/library/ms678421.aspx

Note This change in behavior does not affect applications that are already compiled and installed. This article describes functionality that can now be applied in Windows Server 2003 Service Pack 2 (SP2). For more information, 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

Keywords: kbbug kbfix kbqfe kbpubtypekc kbhotfixserver kbwinserv2003sp2fix KB911647

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