From secnotif@MICROSOFT.COM Fri Sep 3 21:00:04 1999 From: Microsoft Product Security Resent-From: mea culpa To: MICROSOFT_SECURITY@ANNOUNCE.MICROSOFT.COM Resent-To: jericho@attrition.org Date: Fri, 3 Sep 1999 20:21:21 -0700 Subject: Microsoft Security Bulletin (MS99-034) The following is a Security Bulletin from the Microsoft Product Security Notification Service. Please do not reply to this message, as it was sent from an unattended mailbox. ******************************** Microsoft Security Bulletin (MS99-034) -------------------------------------- Patch Available for "Fragmented IGMP Packet" Vulnerability Originally Posted: September 03, 1999 Summary ======= Microsoft has released a patch that eliminates a vulnerability in the TCP/IP stack implementations of Microsoft(r) Windows(r) 95, Windows 98 and Windows NT(r) 4.0. Fragmented IGMP packets can cause a variety of problems in Windows 95 and 98, up to and including causing the machine to crash. Windows NT 4.0 contains the same vulnerability, but other system mechanisms make a successful attack much more difficult. Frequently asked questions regarding this vulnerability can be found at http://www.microsoft.com/security/bulletins/MS99-034faq.asp Issue ===== By sending fragmented IGMP packets to a Windows 95, 98 or Windows NT 4.0 machine, it is possible to disrupt the normal operation of the machine. This vulnerability primarily affects Windows 95 and 98 machines. Depending on a variety of factors, sending such packets to a Windows 95 or 98 machine may elicit behavior ranging from slow performance to crashing. Windows NT contains the same vulnerability, but other system mechanisms compensate and make it much more difficult to mount a successful attack. Affected Software Versions ========================== - Microsoft Windows 95 - Microsoft Windows 98 - Microsoft Windows 98 Second Edition - Microsoft Windows NT Workstation 4.0 - Microsoft Windows NT Server 4.0 - Microsoft Windows NT Server 4.0, Enterprise Edition - Microsoft Windows NT Server 4.0, Terminal Server Edition Patch Availability ================== - Windows 95: This patch will be available shortly - Windows 98: http://www.microsoft.com/windows98/downloads/corporate.asp - Windows NT Workstation 4.0; Windows NT Server 4.0; Windows NT Server, Enterprise Edition: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa /NT40/hotfixes-postSP5/IGMP-fix/ - Windows NT Server 4.0, Terminal Server Edition: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa /NT40TSE/hotfixes-postSP5/IGMP-fix/ NOTE: Line breaks have been inserted into the above URLs for readability. NOTE: The Windows 95 and 98 patches also will be available via WindowsUpdate (http://www.microsoft.com/windowsupdate) circa September 9, 1999. More Information ================ Please see the following references for more information related to this issue. - Microsoft Security Bulletin MS99-034: Frequently Asked Questions, http://www.microsoft.com/security/bulletins/MS99-034faq.asp. - Microsoft Knowledge Base (KB) article Q238329, Fragmented IGMP Packets may Promote Denial of Service, http://support.microsoft.com/support/kb/articles/q238/3/29.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. Revisions ========= - September 03, 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. Terms of Use. ******************************************************************* You have received this e-mail bulletin as a result of your registration to the Microsoft Product Security Notification Service. You may unsubscribe from this e-mail notification service at any time by sending an e-mail to MICROSOFT_SECURITY-SIGNOFF-REQUEST@ANNOUNCE.MICROSOFT.COM The subject line and message body are not used in processing the request, and can be anything you like. For more information on the Microsoft Security Notification Service please visit http://www.microsoft.com/security/services/bulletin.asp. For security-related information about Microsoft products, please visit the Microsoft Security Advisor web site at http://www.microsoft.com/security.