Microsoft Security Bulletin (MS99-057)

--------------------------------------



Patch Available for "Malformed Security Identifier Request" Vulnerability

Originally Posted: December 16, 1999



Summary

=======

Microsoft has released a patch that eliminates a vulnerability in

Microsoft(r) Windows NT(r) 4.0.  The vulnerability could allow a malicious

user to cause a Windows NT machine to stop responding  to requests for

service. The patch for this vulnerability is included in the

previously-released  patch for the "Syskey Keystream Reuse" vulnerability;

customers who have already applied it do  not need to take any further

action.



Frequently asked questions regarding this vulnerability can be found at

http://www.microsoft.com/security/bulletins/MS99-057faq.asp.



Issue

=====

The Windows NT Local Security Authority (LSA) provides a number of functions

for enumerating and  manipulating security information. One of these

functions, LsaLookupSids(), is used to determine  the Security Identifier

(SID) associated with a particular user or group name. A flaw in the

implementation of this function causes it to incorrectly handle certain

types of invalid  arguments. If an affected call were made to this function,

it would cause the LSA to crash,  thereby preventing the machine from

performing useful work.



An affected machine could be put back into service by rebooting, with the

loss of any work that  was in progress at the time. Remote attacks via this

vulnerability would not be possible if  NetBios is filtered at the firewall.





Affected Software Versions

==========================

 - Microsoft Windows NT Workstation 4.0

 - Microsoft Windows NT Server 4.0

 - Microsoft Windows NT Server 4.0, Enterprise Edition

 - Microsoft Windows NT Server 4.0, Terminal Server Edition



Patch Availability

==================



 - This fix for this vulnerability is included in the patch

   for the "Syskey Keystream Reuse" vulnerability. (See

   http://www.microsoft.com/Security/Bulletins/ms99-056.asp for

   more information on this vulnerability).  Customers who

   have already applied it do not need to take any additional action.



NOTE: Additional security patches are available at the Microsoft Download

Center



More Information

================

Please see the following references for more information related to this

issue.

 - Microsoft Security Bulletin MS99-057: Frequently Asked Questions,

   http://www.microsoft.com/security/bulletins/MS99-057faq.asp.

 - Microsoft Knowledge Base (KB) article Q248185,

   SID Enumeration Function in LSA may not Handle Argument Properly,

   http://support.microsoft.com/support/kb/articles/q248/1/85.asp.

   (Note: It may take 24 hours from the original posting of this bulletin

   for this KB article to be visible.)

 - Microsoft Security Bulletin MS99-056:

   Patch Available for "Syskey Keystream Reuse" Vulnerability,

   http://www.microsoft.com/Security/Bulletins/ms99-056.asp.

 - Microsoft Security Advisor web site,

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



Obtaining Support on this Issue

===============================

This is a fully supported patch. Information on contacting Microsoft

Technical Support is available at

http://support.microsoft.com/support/contact/default.asp.



Acknowledgments

===============

Microsoft acknowledges Anthony Osborne of the Security Labs of Network

Associates for bringing  this issue to our attention.



Revisions

=========

 - December 16, 1999: Bulletin Created.



---------------------------------------------------------------------



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.



(c) 1999 Microsoft Corporation. All rights reserved. Terms of Use.