From secnotif@MICROSOFT.COM Mon Sep 20 18:25:59 1999 From: Microsoft Product Security Resent-From: mea culpa To: MICROSOFT_SECURITY@ANNOUNCE.MICROSOFT.COM Resent-To: jericho@attrition.org Date: Mon, 20 Sep 1999 16:06:09 -0700 Subject: Microsoft Security Bulletin (MS99-038) 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 (MS99-038) -------------------------------------- Patch Available for "Spoofed Route Pointer" Vulnerability Originally Posted: September 20, 1999 Summary ======= Microsoft has released a patch that eliminates a vulnerability in Microsoft(r) Windows(r) 95, 98 and Windows NT(r) 4.0 that could allow source routing to be performed, even if it has ostensibly been disabled. The patch also includes added functionality to provide additional control over source routing. Frequently asked questions regarding this vulnerability can be found at http://www.microsoft.com/security/bulletins/ms99-038faq.asp Issue ===== Windows NT 4.0 Service Pack 5 introduced the ability to disable source routing on a multi-homed Windows NT machine that acts as a router. However, even if source routing is disabled, it is possible to bypass it by including a specific type of incorrect information within the route pointer in the data packet. Windows 95 and 98 also provide this capability, and are affected by the same vulnerability. The patch restores correct operation to the anti-source routing feature. In addition, it provides additional functionality that enables source routing to be disabled on single-homed machines and on multi-homed machines that are not used as routers. Customers who are using multi-homed Windows 95, 98 or or Windows NT machines, and who wish to disable source routing should apply the patch to ensure proper operation of the anti-source routing features. In addition, customers who have non-routing machines in vulnerable locations (for example, single-homed machines outside of a firewall or multi-homed machines joining two subnets) may wish to install the patch in order to use the new functionality to disable source routing in these cases as well. 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, 98 and Windows 98 Second Edition: To be released shortly - Windows NT 4.0 Workstation, Windows NT 4.0 Server and Windows NT 4.0 Server, Enterprise Edition: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/ usa/nt40/Hotfixes-PostSP5/Spoof-fix - Windows NT 4.0 Server, Terminal Server Edition: To be released shortly NOTE: Line breaks have been inserted into the URLs above for readability More Information ================ Please see the following references for more information related to this issue. - Microsoft Security Bulletin MS99-038: Frequently Asked Questions, http://www.microsoft.com/security/bulletins/ms99-038faq.asp. - Microsoft Knowledge Base (KB) article Q238453, Pointer in Source Route Option Bypasses Source Routing Disable, http://support.microsoft.com/support/kb/articles/q238/4/53.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 Network Associates, Inc. (http://www.nai.com) for bringing this issue to our attention and working with us to alert customers about it. Revisions ========= - September 20, 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. 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