Microsoft KB Archive/915787

= The certificate validation fails on client computers when Internet Explorer 6 uses CAPI to retrieve the CRL or the CA certificates =

Article ID: 915787

Article Last Modified on 9/11/2007

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APPLIES TO

 Microsoft Internet Explorer 6.0, when used with:  Microsoft Windows XP Service Pack 2

 Microsoft Windows Server 2003 SP1 

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Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry



SYMPTOMS
You configure a proxy server that uses basic authentication or digest authentication in the network. The client computers can access the Internet through the proxy server. In this scenario, you may notice that the certificate validation on the client computers fails when Microsoft Internet Explorer 6 validates the certificate by using Cryptography API (CAPI) to retrieve the Certificate Revocation List (CRL). This problem also occurs when Internet Explorer 6 updates the certificates from certification authority (CA).

When you check the network traffic in the Microsoft Network Monitor, you will find the following error message:

HTTP 407 Proxy Authentication Required



CAUSE
This issue occurs because that the proxy server cannot authenticate the user credential when CAPI tries to retrieve the CRL or tries to update the certificates from CA.

On Windows XP SP2 and other advanced operating systems, the CAPI certificate uses the WinHTTP.dll process instead of the WinINet.dll process for network retrieval. The user credential is not shared in memory between WinINet.dll and WinHTTP.dll in Internet Explorer. The WinHTTP.dll process is noninteractive. The WinHTTP.dll process does not prompt the user for user credential. Therefore, when CAPI communicates with the proxy server over WinHTTP.dll, the proxy authentication fails because the user credential is unavailable.



Windows XP
A supported hotfix is now 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 service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or 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. To create a separate service request, visit the following Microsoft Web site:

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

Prerequisites
To apply this hotfix, you must have Windows XP Service Pack 2 (SP2) installed on the computer.

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

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

Registry information
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

Create and then enable the ShareCredsWithWinHttp registry entry after you apply this hotfix. To do this, follow these steps: <ol> Click Start, click Run, type regedit, and then click OK.</li> Locate the following registry subkey:

</li> Right-click the registry subkey, point to New, and then click DWORD Value.</li> Type ShareCredsWithWinHttp, and then press ENTER.</li> Right-click ShareCredsWithWinHttp, and then click Modify.</li> In the Value data box, type 1, and then click OK.</li> Exit Registry Editor.</li></ol>

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 XP with Service Pack 2, x86-based versions

<pre class="fixed_text">

Windows Server 2003
A supported hotfix is now 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 service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or 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. To create a separate service request, visit the following Microsoft Web site:

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

Prerequisites
To apply this hotfix, you must have Windows Server 2003 Service Pack 1 (SP1) installed on the computer.

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

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

Registry information
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To enable this hotfix, add the ShareCredsWithWinHttp registry entry. To do this, follow these steps: <ol> Click Start, click Run, type regedit, and then click OK.</li> Locate the following registry subkey:

</li> Right-click the registry subkey, point to New, and then click DWORD Value.</li> Type ShareCredsWithWinHttp, and then press ENTER.</li> Right-click ShareCredsWithWinHttp, and then click Modify.</li> In the Value data box, type 1, and then click OK.</li> Exit Registry Editor.</li></ol>

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 Service Pack 1, x86-based versions

Windows Server 2003, x64-based versions

Windows Server 2003 with Service Pack 1, Itanium-based versions

<div class="status_section">

STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.

<div class="moreinformation_section">

MORE INFORMATION
After you apply this hotfix, WinINet.dll can send the user credential to WinHTTP.dll.

For more information about how to use Network Monitor to capture network traffic, click the following article number to view the article in the Microsoft Knowledge Base:

812953 How to use Network Monitor to capture network traffic

For more information about the changes to the CryptoAPI certificate chain validation logic in Windows XP Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base:

887196 Summary of changes to the CryptoAPI certificate chain validation logic in Windows XP Service Pack 2

For more information about the standard terminology that is used to describe Microsoft software updates, 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 kbexpertiseinter kbhotfixserver KB915787

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