Microsoft Security Bulletin (MS00-025)

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Microsoft Security Bulletin (MS00-025)
- --------------------------------------

Procedure Available to Eliminate "Link View Server-Side Component"
Vulnerability

Originally Posted: April 14, 2000

Summary
=======
On April 14, 2000, Microsoft issued the original version of this
bulletin, to discuss a security vulnerability affecting  several web
server products. Shortly after publishing the bulletin, we learned of
a new, separate vulnerability that  significantly increases the threat
to users of these products. The remediation is the same as originally
described, so any  customers who followed the original recommendations
would not need to take additional steps. However, some customers who
did  not need to take action based on the original assessment may need
to do so now.

A procedure is available to eliminate a security vulnerability that
could allow a malicious user to cause a web server to  crash.
Microsoft is investigating the possibility that the vulnerability also
would allow a malicious user to run arbitrary  code on the server, and
will update this bulletin when this is known.

Frequently asked questions regarding this vulnerability and the
procedure can be found at
http://www.microsoft.com/technet/security/bulletin/fq00-025.asp

Issue
=====
Dvwssr.dll is a server-side component used to support the Link View
feature in Visual Interdev 1.0. However, it contains an  unchecked
buffer. If overrun with random data, it could be used to cause an
affected server to crash.

Microsoft is continuing to investigate this issue in order to
determine whether there also is a capability to run arbitrary  code on
the server. We will update this bulletin when these results are known.
However, the threat posed by the denial of  service case alone is
sufficient to warrant taking the remediation steps detailed below.
Customers who take these steps now  will not need to take additional
steps regardless of the final outcome of the investigation.

Affected Software Versions
==========================
The affected component is part of Visual Interdev 1.0. However, it is
a server-side component, and is included in the  following products:
 - Windows NT 4.0 Option Pack, which is the primary distribution
   mechanism for Internet Information Server 4.0
 - Personal Web Server 4.0, which ships as part of Windows 95 and 98
 - Front Page 98 Server Extensions

NOTE:
1. Windows 2000 is not affected by this vulnerability. Upgrading from
   an affected Windows NT 4.0 to Windows 2000 removes the
   vulnerability.
2. Installing Office 2000 Server Extensions on an affected server
   removes this vulnerability.
3. Installing FrontPage 2000 Server Extensions on an affected server
   removes this vulnerability.

Remediation
===========
To eliminate this vulnerability, customers who are hosting web sites
using any of the affected products should delete all  copies of the
file Dvwssr.dll from their servers. The FAQ provides step-by-step
instructions for doing this. The only  functionality lost by deleting
the file is the ability to generate link views using Visual Interdev
1.0.

More Information
================
Please see the following references for more information related to
this issue.
 - Frequently Asked Questions: Microsoft Security Bulletin MS00-025,
   http://www.microsoft.com/technet/security/bulletin/fq00-025.asp.
 - Microsoft Knowledge Base article Q259799 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
===============================
Information on contacting Microsoft Technical Support is available
at http://support.microsoft.com/support/contact/default.asp.

Revisions
=========
 - April 14, 2000: Bulletin Created.

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

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LIMITATION MAY NOT APPLY.

Last updated April 14, 2000

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

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