Operating System:

Published:

12 June 2000

Protect yourself against future threats.

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              AUSCERT External Security Bulletin Redistribution
                             
           ESB-2000.131 -- Microsoft Security Bulletin (MS00-040)
  Patch Available for "Remote Registry Access Authentication" Vulnerability
                                13 June 2000

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	AusCERT Security Bulletin Summary
	---------------------------------

Product:		Remote Registry Server
Vendor:			Microsoft
Operating System:	Windows NT 4.0
Platform:		N/A

Impact:			Denial of Service
Access Required:	Existing Account

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Microsoft Security Bulletin (MS00-040)
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Patch Available for "Remote Registry Access Authentication" Vulnerability

Originally posted: June 08, 2000

Summary
=======
Microsoft has released a patch that eliminates a security vulnerability in
Microsoft(r) Windows NT 4.0. Under certain  conditions, the vulnerability
could be used to cause a Windows NT 4.0 machine to fail.

Frequently asked questions regarding this vulnerability and
the patch can be found at
http://www.microsoft.com/technet/security/bulletin/fq00-040.asp

Issue
=====
Before a request to access the registry from a remote machine can be
processed, it must first be authenticated by the Remote  Registry server. If
the request is malformed in a specific fashion, it could be misinterpreted
by the remote registry server,  causing it to fail. Because the Remote
Registry server is contained within the winlogon.exe system process on
Windows NT 4.0,  a failure in that process would cause the entire system to
fail.

Only an authenticated user could levy such a request -- an anonymous (or
null-session) connection could not cause this  failure. An affected machine
could be put back into service by rebooting.

Affected Software Versions
==========================
 - Microsoft Windows NT 4.0 Workstation
 - Microsoft Windows NT 4.0 Server
 - Microsoft Windows NT 4.0 Server, Enterprise Edition
 - Microsoft Windows NT 4.0 Server, Terminal Server Edition

Note: Windows 2000 is not affected by this vulnerability.

Patch Availability
==================
 - Microsoft Windows NT 4.0 Workstation, Server, and
   Server, Enterprise Edition:
   http://www.microsoft.com/Downloads/Release.asp?ReleaseID=21772
 - Microsoft Windows NT 4.0 Server, Terminal Server Edition:
   To be released shortly

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.
 - Frequently Asked Questions: Microsoft Security Bulletin MS00-040,
   http://www.microsoft.com/technet/security/bulletin/fq00-040.asp
 - Microsoft Knowledge Base article Q264684 discusses this issue
   and will be available soon.
 - Microsoft TechNet Security web site,
   http://www.microsoft.com/technet/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 thanks  Renaud Deraison from the Nessus Team
(http://www.nessus.org/) for reporting this issue to us and working  with us
to protect customers.

Revisions
=========
 - June 08, 2000: Bulletin Created.

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