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 (911647)

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.

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows Server 2003 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

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, x86-based versions

File name	File version	File size	Date	Time	Platform
Wldap32.dll	5.2.3790.2594	178,688	15-Dec-2005	05:27	x86

Windows Server 2003 with SP1, x64-based versions

File name	File version	File size	Date	Time	Platform	Service pack requirement	Service branch
Wldap32.dll	5.2.3790.2594	399,872	14-Dec-2005	13:56	x64	SP1	Not Applicable
Wwldap32.dll	5.2.3790.2594	178,688	14-Dec-2005	13:56	x86	SP1	WOW

Windows Server 2003 with SP1, Itanium-based versions

File name	File version	File size	Date	Time	Platform	Service pack requirement	Service branch
Wldap32.dll	5.2.3790.2594	454,144	14-Dec-2005	13:57	IA-64	SP1	Not Applicable
Wwldap32.dll	5.2.3790.2594	178,688	14-Dec-2005	13:57	x86	SP1	WOW

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://msdn.microsoft.com/library/default.asp?url=/library/en-us/ldap/ldap/session_options.asp

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://windowssdk.msdn.microsoft.com/en-us/library/ms720552.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