Microsoft Security Bulletin (MS00-017)

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Microsoft Security Bulletin (MS00-017)
--------------------------------------

Patch Available for "DOS Device in Path Name" Vulnerability

Originally Posted: March 16, 2000

Summary
=======
Microsoft has released a patch that eliminates a security vulnerability in
Microsoft(r) Windows(r) 95, Windows 98, and Windows 98 Second Edition. The
vulnerability could cause a user's system to crash, if they attempted to
access a file or folder whose path contained certain reserved words.

Frequently asked questions regarding this vulnerability can be found
at http://www.microsoft.com/technet/security/bulletin/fq00-017.asp.

Issue
=====
DOS device names are reserved words, and cannot be used as folder or file
names. When parsing a reference to a file or folder, Windows correctly
checks for the case in which a single DOS device name is used in the path,
and treats it as invalid. However, it does not check for the case in which
the path includes multiple DOS device names. When Windows attempts to
interpret the device name as a file resource, it performs an illegal
resource access that usually results in a crash.

Because it is not possible to create files or folders that contain DOS
device names, it would be unusual for a user to try to access one under
normal circumstances. The chief threat posed by this vulnerability is that a
malicious user could attempt to entice a user to attempt such an access. For
instance, if a web site operator hosted a hyperlink that referenced such a
path, clicking the link would result in the user's machine crashing.
Likewise, a web page or HTML mail that specified a local file as the source
of rendering information could cause the user's machine to crash when it was
displayed. If this happened, the machine could be put back into normal
service by restarting it.

Affected Software Versions
==========================
 - Microsoft Windows 95
 - Microsoft Windows 98
 - Microsoft Windows 98 Second Edition

Patch Availability
==================
 - Windows 95:
   http://www.microsoft.com/downloads/release.asp?releaseID=19491
 - Windows 98 and Windows 98 Second Edition:
   http://www.microsoft.com/downloads/release.asp?ReleaseID=19389

NOTE: Additional security patches are available at the Microsoft Download
Center

NOTE: The patch will be available shortly at the WindowsUpdate site. When
this happens, we will modify the bulletin to provide additional information.

More Information
================
Please see the following references for more information related to this
issue.
 - Microsoft Security Bulletin MS00-017: Frequently Asked Questions,
   http://www.microsoft.com/technet/security/bulletin/fq00-017.asp
 - Microsoft Knowledge Base article Q256015 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
Technical Support is available at
http://support.microsoft.com/support/contact/default.asp

Revisions
=========
 - March 16, 2000: Bulletin Created.

Last updated March 16, 2000

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

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