-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft Windows 95 and 98 Telnet Client Vulnerability September 24, 1999 21:00 GMT Number J-070 ______________________________________________________________________________ PROBLEM: A vulnerability was identified with the Telnet client that ships as part of Microsoft Windows 95 and 98 that may allow a web page visited by the user to run arbitrary code on the user's computer. PLATFORM: Microsoft Windows 95, 98, and 98 Second Edition. DAMAGE: A classic buffer overflow may allow arbitrary code to be executed on the user's computer. SOLUTION: Apply the available patches. ______________________________________________________________________________ VULNERABILITY The risk is low. A user would have to visit a web site and view ASSESSMENT: a web page especially constructed to exploit this vulnerability. ______________________________________________________________________________ [Start Microsoft Advisory] 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. - ------------------------------------------------------------------ THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF 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. (c) 1999 Microsoft Corporation. All rights reserved. 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[End Microsoft Advisory] ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft Corporation for the information contained in this bulletin. ______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. 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If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. 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LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC) J-060: Microsoft Office "ODBC" Vulnerabilities J-061: Lotus Notes Domino Server Denial of Service Attacks J-062: Netscape Enterprise and FastTrack Web Servers Buffer Overflow J-063: Domain Name System (DNS) Denial of Service (DoS) Attacks J-064: ActiveX Controls, Scriptlet.typlib & Eyedog, Vulnerabilities J-065: Wu-ftpd Vulnerability J-066: FreeBSD File Flags and Man-In-The-Middle Attack J-067: Profiling Across FreeBSD Exec Calls J-068: FreeBSD Vulnerabilities in wu-ftpd and proftpd J-069: SunOS LC_MESSAGES Environment Variable Vulnerability -----BEGIN PGP SIGNATURE----- Version: 4.0 Business Edition iQCVAwUBN/D3DrnzJzdsy3QZAQGi8AP/fxo/OEY5EoTmxJk1YsQFIFkmaC/yygx9 3rgLLVgngKulkho59RyfNoQEGFAN2Mt2vz2P7M06UY8Ztu2MFSEyIs89tbH4eKx0 Y2FgI9WqpovnyZcyiPHkny5KERuH0qy9wgha/rNX7RDxhw3zwhLydlCxq0EUxuIv BQZPHsWIimc= =u74S -----END PGP SIGNATURE-----