DOCUMENT:Q231457 16-MAY-2002 [winnt] TITLE :Malformed Request Causes LSA Service to Stop Responding PRODUCT :Microsoft Windows NT PROD/VER::4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4,4.0 SP5 OPER/SYS: KEYWORDS:kbProgramming kbWinNT4sp6fix ====================================================================== ------------------------------------------------------------------------------- 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 ------------------------------------------------------------------------------- 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 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.