K-019: Microsoft - "Spoofed LPC Port Request" Vulnerability

PROBLEM:       A function which supports LPC (Local Procedure Calls) is
               flawed. A malicious user through a series of steps could fool
               the validation checking in the function into believing the user
               has higher privileges.
PLATFORM:      Microsoft Windows NT 4.0 Workstation, Microsoft Windows NT 4.0
               Server, Microsoft NT 4.0 Server (Enterprise Edition), Microsoft
               Windows NT 4.0 Server (Terminal Server Edition)
DAMAGE:        A malicious user could logon to a Windows NT 4.0 machine and
               run a program posing as another user or the Administrator of
               the machine.
SOLUTION:      Install the hotfix from Microsoft.
VULNERABILITY  The risk is low. A malicious user would need to have local
ASSESSMENT:    access to the machine and be able to, through a series of
               complicated steps, spoof the validation checking of an LPC
               function.


[ Begin Microsoft Security Bulletin ]

Microsoft Security Bulletin (MS00-003)
--------------------------------------

Patch Available for "Spoofed LPC Port Request" Vulnerability
Originally Posted: January 13, 2000

Summary
=======
Microsoft has released a patch that eliminates a security vulnerability in
Microsoft(r) Windows NT(r) 4.0. The vulnerability could allow a user logged
onto a Windows NT 4.0 machine from the keyboard to become an administrator
on the machine.

Frequently asked questions regarding this vulnerability can be found at
http://www.microsoft.com/security/bulletins/MS00-003faq.asp.

Issue
=====
LPC Ports is a facility that allows LPC calls on a machine. One of the
functions in the LPC Ports API set enables, by design, a server thread to
impersonate a client thread on the same machine. However, a flaw in the
validation portion of the function would allow a malicious user to create
both the client and server threads, and manipulate the impersonation request
to allow it to run in the context of any desired user on the local machine,
including the System itself.

The primary risk from this vulnerability is that a malicious user could
exploit this vulnerability to gain additional privileges on the local
machine. However, it also could be used to cause audit logs to indicate that
certain actions were taken by another user. A malicious user would require
the ability to log onto the target machine interactively and run arbitrary
programs in order to exploit this vulnerability, and as a result,
workstations and terminal servers would be at greatest risk.

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

Patch Availability
==================
 - Microsoft Windows NT 4.0 Workstation, Server and Server, Enterprise
Edition:
   Intel:
      http://www.microsoft.com/downloads/release.asp?ReleaseID=17382
   Alpha:
      http://www.microsoft.com/downloads/release.asp?ReleaseID=17383
 - 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.
 - Microsoft Security Bulletin MS00-003: Frequently Asked Questions,
   http://www.microsoft.com/security/bulletins/MS00-003faq.asp.
 - Microsoft Knowledge Base (KB) article Q247869,
   Local Procedure Call may Permit Unauthorized Account Usage,
   http://support.microsoft.com/support/kb/articles/q247/8/69.asp.
   (Note: It may take 24 hours from the original posting of this bulletin
   for the KB article to be visible.)
 - 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 thanks Bindview's RAZOR Security Team (www.bindview.com) for
reporting this issue to us and working with us to protect customers.

Revisions
=========
 - January 13, 2000: 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) 2000 Microsoft Corporation. All rights reserved. Terms of Use

[ End Microsoft Security Bulletin ]

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