A user is not successfully authenticated when NTLMv2 authentication is used on a Windows Server 2003-based IAS server (893318)


The information in this article applies to:

  • Microsoft Windows Server 2003, Datacenter Edition for Itanium-based Systems
  • Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems
  • Microsoft Windows Server 2003, Datacenter Edition
  • Microsoft Windows Server 2003, Enterprise Edition
  • Microsoft Windows Server 2003, Standard Edition


Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SYMPTOMS

Consider a scenario in which the following conditions are true:
  • A Microsoft Windows Server 2003-based Internet Authentication Service (IAS) server uses NTLM version 2 (NTLMv2) user authentication.
  • To connect to the IAS server, a client user uses a virtual private network (VPN) connection that uses Microsoft Challenge Handshake Authentication Protocol (MS-CHAP).
In this scenario, when the user uses the VPN connection to connect to the IAS server, the IAS server does not authenticate the user.

CAUSE

This problem occurs because MS-CHAP is designed to be compatible only with NTLM version 1 authentication.

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

No prerequisites are required.

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 tool in Control Panel.
Windows Server 2003, 32-bit versions
   Date         Time   Version          Size  File name
   -------------------------------------------------------
   04-Feb-2005  02:57  5.2.3790.264   34,304  Aaaamon.dll      
   18-Oct-2004  14:12  5.2.3790.212   64,000  Eventlog.dll     
   04-Feb-2005  02:57  5.2.3790.264  102,400  Iassam.dll       
   04-Feb-2005  02:57  5.2.3790.264  801,792  Lsasrv.dll       
   04-Feb-2005  02:57  5.2.3790.264  130,048  Msv1_0.dll       
   04-Feb-2005  02:57  5.2.3790.264  108,544  Raschap.dll
Windows Server 2003, 64-bit versions
   Date         Time   Version            Size  File name     Platform
   -------------------------------------------------------------------
   03-Feb-2005  13:24  5.2.3790.264     62,464  Aaaamon.dll   IA-64
   17-Oct-2004  19:30  5.2.3790.212    167,936  Eventlog.dll  IA-64
   03-Feb-2005  13:24  5.2.3790.264    336,384  Iassam.dll    IA-64
   03-Feb-2005  13:24  5.2.3790.264  2,039,808  Lsasrv.dll    IA-64
   03-Feb-2005  13:24  5.2.3790.264    342,528  Msv1_0.dll    IA-64
   03-Feb-2005  13:24  5.2.3790.264    204,288  Raschap.dll   IA-64
   03-Feb-2005  13:27  5.2.3790.264     34,304  Waaaamon.dll  x86
   03-Feb-2005  13:27  5.2.3790.264    102,400  Wiassam.dll   x86
   03-Feb-2005  13:27  5.2.3790.264    130,048  Wmsv1_0.dll   x86
   03-Feb-2005  13:27  5.2.3790.264    108,544  Wraschap.dll  x86


To enable NTLMv2 authentication, you must add a new registry entry after you apply the hotfix. To do this, follow these steps.

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
  1. Click Start, click Run, type regedit in the Open box, and then click OK.
  2. Locate and then click the following registry subkey:

    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\RemoteAccess\Policy

  3. On the Edit menu, point to New, and then click DWORD Value.
  4. Type Enable NTLMv2 Compatibility, and then press ENTER.
  5. On the Edit menu, click Modify.
  6. In the Value data box, type 1, and then click OK.
  7. Quit 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 additional information about NTLM authentication, click the following article numbers to view the articles in the Microsoft Knowledge Base:

239869 How to enable NTLM 2 authentication

147706 How to disable LM authentication on Windows NT

For additional information about 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

Modification Type:MajorLast Reviewed:4/7/2006
Keywords:kbQFE KBHotfixServer kbBug kbfix kbWinServ2003preSP1fix KB893318 kbAudITPRO
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