Microsoft Security Bulletin (MS00-005)
--------------------------------------

Patch Available for "Malformed RTF Control Word" Vulnerability
Originally Posted: January 17, 2000

Summary
=======
Microsoft has released a patch that eliminates a security vulnerability in
the Rich Text Format (RTF) reader that ships as  part of Microsoft(r)
Windows(r) 95 and 98, and Windows NT(r) 4.0. Under certain conditions, the
vulnerability could be used  to cause email programs to crash.

Frequently asked questions regarding this vulnerability can be found at
http://www.microsoft.com/security/bulletins/MS00-005faq.asp.

Issue
=====
RTF files consist of text and control information. The control information
is specified via directives called control words.  The default RTF reader
that ships as part of many Windows platforms has an unchecked buffer in the
portion of the reader that  parses control words. If an RTF file contains a
specially-malformed control word, it could cause the application to crash.

Microsoft believes that this is a denial of service vulnerability only, and
that there is no capability to use this  vulnerability to run arbitrary
code. The most serious risk from this vulnerability would result if a user
had preview mode  enabled on a mail program like Outlook, and received an
email that exploited the vulnerability. Because preview mode causes  the
mail to be parsed without user assent, the mail program would continue to
crash until a subsequent mail was received or  the mail program was started
with preview mode disabled.

Affected Software Versions
==========================
 - Microsoft Windows 95
 - Microsoft Windows 98
 - Microsoft Windows 98 Second Edition
 - Microsoft Windows NT 4.0 Workstation
 - Microsoft Windows NT 4.0 Server
 - Microsoft Windows NT 4.0 Server, Enterprise Edition
 - Microsoft Windows NT 4.0 Server, Terminal Server Edition

NOTE: Windows 2000 is not affected by this vulnerability.

Patch Availability
==================
 - Windows 95:
   http://www.microsoft.com/windows95/downloads/contents/
   WUCritical/rtfcontrol/default.asp
 - Window 98:
   http://www.microsoft.com/windows98/downloads/contents/
   WUCritical/rtfcontrol/default.asp
 - Windows NT 4.0 Workstation, Windows NT 4.0 Server, and
   Windows NT 4.0 Server, Enterprise Edition:
   Intel:
      http://www.microsoft.com/Downloads/Release.asp?ReleaseID=17510
   Alpha:
      http://www.microsoft.com/Downloads/Release.asp?ReleaseID=17511
 - Windows NT 4.0 Server, Terminal Server Edition:
   To be released shortly.

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

NOTE: The Windows 95 and 98 versions of the patch will also be available via
WindowsUpdate shortly. When this happens, we  will modify the bulletin to
note this fact.

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 MS00-005,
   http://www.microsoft.com/security/bulletins/MS00-005faq.asp.
 - Microsoft Knowledge Base (KB) article Q249973,
   Default RTF File Viewer Interrupts Normal Application Processing,
   http://support.microsoft.com/support/kb/articles/q249/9/73.asp.
   (Note: It may take 24 hours from the original posting of this bulletin
   for this KB article to be visible.)
 - Rich Text Format (RTF) Specification and Sample RTF Reader Program,
   Version 1.5,
   http://msdn.microsoft.com/library/specs/
   richtextformatrtfspecificationsamplertfreaderprogramversion15.htm
 - Microsoft Security Advisor web site,
   http://www.microsoft.com/security/default.asp.

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

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
=========
 - January 17, 2000: Bulletin Created.

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