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Microsoft Security Bulletin (MS00-063)
- --------------------------------------

Patch Available for "Invalid URL" Vulnerability
Originally posted: September 05, 2000

Summary
=======
Microsoft has released a patch that eliminates a security
vulnerability in Microsoft(r)  Internet Information Server (IIS). The
vulnerability could enable a malicious user to  prevent an affected
web server from providing useful service.

Frequently asked questions regarding this vulnerability and the patch
can be found at
http://www.microsoft.com/technet/security/bulletin/fq00-063.asp

Issue
=====
If an affected web server received a particular type of invalid URL,
it could, under certain  conditions, start a chain of events that
would culminate in an invalid memory request that would cause the IIS
service to fail. This would prevent the server from providing web
services.

This vulnerability does not provide the opportunity to compromise any
data on the server or to usurp any administrative privileges on the
server. An affected machine could be put back into service by
restarting the IIS service.

Although the effect of the vulnerability manifests itself through
IIS, the underlying  problem actually lies within Windows NT 4.0.
Microsoft engineers worked extensively to  identify scenarios for
exploiting the vulnerability directly through Windows NT 4.0, but did
not find any - the only scenarios identified to date involve IIS.
Nevertheless, it is  possible that scenarios for exploiting the
vulnerability through Windows NT 4.0 do exist,  and as a result, we
recommend that customers using Windows NT 4.0 consider applying the
patch.

Affected Software Versions
==========================
 - Microsoft Internet Information Server 4.0

Note: As noted above in "Issue", the root cause of this vulnerability
lies in Windows NT  4.0, and Microsoft recommends that customers
using Windows NT 4.0 consider applying the  patch.

Patch Availability
==================
 - Microsoft Windows NT 4.0 Workstation, Server and Server,
   Enterprise Edition:
   http://www.microsoft.com/Downloads/Release.asp?ReleaseID=24079
 - 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 MS00-063,
   http://www.microsoft.com/technet/security/bulletin/fq00-063.asp
 - Microsoft Knowledge Base article Q271652 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
Product Support  Services is available at
http://support.microsoft.com/support/contact/default.asp.

Acknowledgments
===============
Microsoft thanks Peter Grundl of VIGILANTe (http://www.vigilante.com)
for reporting this  issue to us and working with us to protect
customers.

Revisions
=========
 - September 05, 2000: Bulletin Created.

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

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"AS IS" WITHOUT  WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL
WARRANTIES, EITHER EXPRESS OR IMPLIED,  INCLUDING THE WARRANTIES OF
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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
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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.
Last Updated September 05, 2000
(c) 2000 Microsoft Corporation. All rights reserved. Terms of use.

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