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Microsoft Security Bulletin (MS99-033)

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



Patch Available for "Malformed Telnet Argument" Vulnerability

Originally Posted: September 09, 1999



Summary

=======

Microsoft has released a patch that eliminates a vulnerability in the Telnet

client that ships as  part of Microsoft(r) Windows(r) 95 and 98. The

vulnerability could allow arbitrary code to be  executed on the user's

computer.



Frequently asked questions regarding this vulnerability can be found at

http://www.microsoft.com/security/bulletins/MS99-033faq.asp



Issue

=====

The Telnet client that ships as part of Windows 95 and 98 has an unchecked

buffer. A  specially-malformed argument could be passed to the client via a

web page in order to cause  arbitrary code to execute on the computer via a

classic buffer overrun technique.



Affected Software Versions

==========================

 - Microsoft Windows 95

 - Microsoft Windows 98

 - Microsoft Windows 98 Second Edition



Patch Availability

==================

 - Microsoft Windows 95

   http://www.microsoft.com/windows95/downloads/contents/

   WUCritical/Telnet/Default.asp

 - Microsoft Windows 98 and Windows 98 Second Edition

   http://www.microsoft.com/windows98/downloads/contents/

   WUCritical/Telnet/Default.asp



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



NOTE: This patch also will be available via WindowsUpdate

(www.microsoft.com/windowsupdate) circa September 10, 1999.



More Information

================

Please see the following references for more information related to this

issue.

 - Microsoft Security Bulletin MS99-033: Frequently Asked Questions,

   http://www.microsoft.com/security/bulletins/MS99-033faq.asp.

 - Microsoft Knowledge Base (KB) article Q240163,

   Buffer Overrun in Telnet in Windows 98 Poses a Security Risk,

   http://support.microsoft.com/support/kb/articles/q240/1/63.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 Jeremy Kothe for bringing this issue to our

attention.



Revisions

=========

 - September 09, 1999: Bulletin Created.



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(c) 1999 Microsoft Corporation. All rights reserved. Terms of Use.



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