Microsoft Security Bulletin (MS99-049)

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Microsoft Security Bulletin (MS99-049)
--------------------------------------

Patch Available for "File Access URL" Vulnerability
Originally Posted: November 12, 1999

Summary
=======
Microsoft has released a patch that eliminates a vulnerability in
Microsoft Windows 95 or Windows 98. The vulnerability could allow
a malicious web site or e-mail message to cause the Windows
machine to crash, or to run arbitrary code.

Frequently asked questions regarding this vulnerability can be
found at http://www.microsoft.com/security/bulletins/MS99-049faq.asp.

Issue
=====
There is a buffer overflow in the Windows 95 and Windows 98
networking software that processes file name strings. If the
networking software were provided with a very long random string
as input, it could crash the machine. If provided with a
specially-malformed argument, it could be used to run arbitrary
code on the machine via a classic buffer overrun attack.

The vulnerability could be exploited remotely in cases where a
file:// URL or a Universal Naming Convention (UNC) string on a
remote web site included a long file name or where a long file
name was included in an e-mail message.

Affected Software Versions
==========================
The buffer overrun is present in the networking software in all
versions of Windows 95 and Windows 98.

Patch Availability
==================
 - Windows 95:
   http://download.microsoft.com/download/win95/update/245729/
   w95/en-us/245729us5.exe
 - Windows 98:
   http://download.microsoft.com/download/win98/update/245729/
   w98/en-us/245729us8.exe

  NOTE: Line breaks have been inserted into the above URLs for readability.

More Information
================
Please see the following references for more information related to this
issue.

 - Microsoft Security Bulletin MS99-049: Frequently Asked Questions,
   http://www.microsoft.com/security/bulletins/MS99-049faq.asp.
 - Microsoft Knowledge Base (KB) article Q245729, Windows 95 and
   98 File Access URL Update,
   http://support.microsoft.com/support/kb/articles/q245/7/29.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 acknowledges UNYUN, the Shadow Penguin Security Research
Group of Japan for bringing this issue to our attention.

Revisions
=========
 - November 12, 1999: Bulletin Created.

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