The following is a Security Bulletin from the Microsoft Product Security
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Microsoft Security Bulletin (MS00-025)
Procedure Available to Eliminate "Link View Server-Side Component"
Originally Posted: April 14, 2000
Updated: April 17, 2000
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 increased the threat to users of
these products. We updated the bulletin later on April 14, 2000, to
advise customers of the new vulnerability, and noted that we would
provide additional details when known. On April 17, 2000, we updated
the bulletin again to provide those details.
A procedure is available to eliminate a security vulnerability that
could allow a malicious user to cause a web server to crash, or
potentially run arbitrary code on the server, if certain permissions
have been changed from their default settings to inappropriate ones.
Although this bulletin has been updated several times as the
investigation of this issue has progressed, the remediation steps
have always remained the same - customers running affected web servers
should delete the affected file, Dvwssr.dll. Customers who have done
this at any point in the past do not need to take any further action.
Frequently asked questions regarding this vulnerability and
the procedure can be found at
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, or could allow arbitrary code to run on the
server in a System context.
By default, the affected component, Dvwssr.dll, resides in a folder
whose permissions only allow web authors to execute it. Under these
conditions, only a person with web author privileges could exploit the
vulnerability - but a web author already has the ability to upload
and execute code of his choice, so this case represents little
additional threat. However, if the permissions on the folder were set
inappropriately, or the .dll were copied to a folder with lower
permissions, it could be possible for other users to execute the
component and exploit the vulnerability.
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:
- Microsoft(r) Windows NT(r) 4.0 Option Pack, which is the
primary distribution mechanism for Internet Information
- Personal Web Server 4.0, which ships as part of
Windows(r) 95 and 98
- Front Page 98 Server Extensions, which ships as part of
Front Page 98.
1. Windows 2000 is not affected by this vulnerability. Upgrading
from an affected Windows NT 4.0 to Windows 2000 removes the
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.
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 of .asp pages using
Visual Interdev 1.0.
Please see the following references for more information related to
- Frequently Asked Questions: Microsoft Security Bulletin MS00-025,
- Microsoft Knowledge Base article Q259799 discusses this issue and
will be available soon.
- Microsoft TechNet Security web site,
Obtaining Support on this Issue
Information on contacting Microsoft Technical Support is available
- April 14, 2000: Bulletin Created.
- April 14, 2000: Bulletin updated to provide preliminary results
of investigation of buffer overrun vulnerability.
- April 17, 2000: Bulletin updated to provide final results of
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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,
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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 April 17, 2000
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