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Q231457: Malformed Request Causes LSA Service to Stop Responding

Article: Q231457
Product(s): Microsoft Windows NT
Version(s): 4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4,4.0 SP5
Operating System(s): 
Keyword(s): kbProgramming kbWinNT4sp6fix
Last Modified: 16-MAY-2002

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The information in this article applies to:

- Microsoft Windows NT Server version 4.0, Terminal Server Edition 
- Microsoft Windows NT Workstation versions 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3, 4.0 SP4, 4.0 SP5 
- Microsoft Windows NT Server versions 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3, 4.0 SP4 
- Microsoft Windows NT Server, Enterprise Edition versions 4.0, 4.0 SP4 
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SYMPTOMS
========

A specially malformed request to the Microsoft Local Security Authority (LSA)
service may be used to exploit a security vulnerability on a computer running
Windows NT. A user can abuse this vulnerability to run a program and cause a
denial of service attack that may cause the LSA service to stop responding
(hang) and require you to restart the computer. You may also receive the
following error message:

  Sorry! The Microsoft Exchange Server is down or the HTTP service has been
  disabled by an administrator. Please try your request again later.

CAUSE
=====

Windows NT provides the ability to manage user privileges programmatically
through the Local Security Authority (LSA) application programming interface
(API). This API allows a program to query user names, modify privileges, and
change other elements of the security policy, subject to the program's
authorizations. Certain API methods do not correctly handle certain types of
invalid arguments. If a call is made using a specially malformed argument, the
LSA service may hang. The vulnerability is a denial of service threat only, and
the LSA service can be restored by restarting the computer. This vulnerability
cannot be used by unauthorized program to query or modify user information or
privileges.

RESOLUTION
==========

Windows NT Server or Workstation 4.0
------------------------------------

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the
individual software update. For information on obtaining the latest service
pack, please go to:

- http://www.microsoft.com/Windows/ServicePacks/

-or-

- Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack

For information on obtaining the individual software update, contact Microsoft
Product Support Services. For a complete list of Microsoft Product Support
Services phone numbers and information on support costs, please go to the
following address on the World Wide Web:

  http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS


NOTE: This fix can be installed on Windows NT 4.0 Service Pack 4 and Service Pack
5.



Windows NT Server 4.0, Terminal Server Edition
----------------------------------------------

To resolve this problem, obtain the latest service pack for Windows NT Server
4.0, Terminal Server Edition. For additional information, please see the
following article in the Microsoft Knowledge Base:

  Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack


STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article. This problem was first corrected in
Windows NT Server version 4.0, Terminal Server Edition Service Pack 6.

MORE INFORMATION
================

For additional security-related information about Microsoft products, please
visit:

  http://www.microsoft.com/security/

Additional query words: MS99-020

======================================================================
Keywords          : kbProgramming kbWinNT4sp6fix 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTW400sp5 kbWinNTW400sp4 kbWinNTW400sp3 kbWinNTW400sp2 kbWinNTW400sp1 kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400sp4 kbWinNTSEnt400 kbWinNTS400sp4 kbWinNTS400sp3 kbWinNTS400sp2 kbWinNTS400sp1 kbWinNTS400search kbWinNTS400 kbNTTermServ400 kbNTTermServSearch
Version           : :4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4,4.0 SP5
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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