Microsoft Security Bulletin (MS00-004)
--------------------------------------

Patch Available for "RDISK Registry Enumeration File" Vulnerability

Originally Posted: January 21, 2000
Revised: February 3, 2000

Summary
=======

On January 21, 2000, Microsoft released the original version of this
bulletin, discussing a  security vulnerability in a Microsoft(r) Windows
NT(r) 4.0 administrative utility. The original  version of the bulletin
discussed the vulnerability within the context of Windows NT 4.0 Server,
Terminal Server Edition. However, we have since learned of scenarios under
which the  vulnerability could also affect Windows NT 4.0 servers and
workstations, and have revised the  bulletin accordingly.

The utility creates a temporary file during execution that can contain
security-sensitive  information, but does not appropriately restrict access
to it. Under certain conditions, it could  be possible for a malicious user
to read the file as it was being created

Frequently asked questions regarding this vulnerability can be found at
http://www.microsoft.com/technet/security/bulletin/fq00-004.asp.

Issue
=====
The RDISK utility is used to create an Emergency Repair Disk (ERD) in order
to record machine  state information as a contingency against system
failure. During execution, RDISK creates a  temporary file containing an
enumeration of the registry. The ACLs on the file allow global read
permission, and as a result, a malicious user who knew that the
administrator was running RDISK  could open the file and read the registry
enumeration information as it was being created. RDISK  erases the file upon
successful completion, so under normal conditions there would be no lasting
vulnerability.

By default, the file is not shared and therefore could not be read by other
network users.

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

Patch Availability
==================
Windows NT 4.0 Workstation; Windows NT 4.0 Server; Windows NT 4.0 Server,
Enterprise Edition:
 - Intel: http://www.microsoft.com/Downloads/Release.asp?ReleaseID=17745
 - Alpha: http://www.microsoft.com/Downloads/Release.asp?ReleaseID=17747

Windows NT 4.0 Server, Terminal Server Edition:
 - http://www.microsoft.com/Downloads/Release.asp?ReleaseID=17384

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 MS00-004,
   http://www.microsoft.com/technet/security/bulletin/fq00-004.asp.
 - Microsoft Knowledge Base (KB) article Q249108,
   Registry Data Is Viewable By All Users After Rdisk Repair Update,
   http://www.microsoft.com/technet/support/kb.asp?ID=249108.
 - Microsoft Knowledge Base (KB) article Q156328,
   Description of Windows NT Emergency Repair Disk,
   http://www.microsoft.com/technet/support/kb.asp?ID=156328
 - Microsoft 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 Arne Vidstrom (http://ntsecurity.nu) for reporting this
issue to us and working  with us to protect customers.

Revisions
=========
 - January 21, 2000: Bulletin Created.
 - February 3, 2000: Bulletin revised to address other affected versions

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

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Last updated Thursday, February 3, 2000

(c) 2000 Microsoft Corporation. All rights reserved. Terms of use

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