Microsoft Security Bulletin (MS00-013) -------------------------------------- Patch Available for "Misordered Windows Media Services Handshake" Vulnerability Originally Posted: February 23, 2000 Summary ======= Microsoft has released a patch that eliminates a security vulnerability in Microsoft(r) Windows Media Services. The vulnerability could allow denial of service attacks against a streaming media server. Frequently asked questions regarding this vulnerability and the patch can be found at http://www.microsoft.com/technet/security/bulletin/fq00-013.asp Issue ===== The handshake sequence between a Windows Media server and a Windows Media Player is asynchronous, because certain resource requests are dependent on the successful completion of previous ones. If the client-side handshake packets are sent in a particular misordered sequence, with certain timing constraints, the server will attempt to use a resource before it has been initialized and will fail catastrophically, causing the Windows Media Unicast Service to crash. The Windows Media Unicast Service can be put back into normal operating condition by restarting the service, but any sessions that were in effect at the time of the crash would need to be restarted. Affected Software Versions ========================== - Microsoft Windows Media Services 4.0 and 4.1 NOTE: Windows NT Server 4.0 customers should upgrade their Windows Media Services installation to Windows Media Services 4.1 before applying the patch. Windows Media Services 4.1 can be downloaded for free from http://www.microsoft.com/windows/windowsmedia/. Windows 2000 Server includes Windows Media Services 4.1, so the patch can be applied directly to this configuration. Patch Availability ================== - Windows NT Server 4.0: http://download.microsoft.com/download/winmediatech40/ Update/4954/NT4/EN-US/WMSU4954_NT4.EXE - Windows 2000 Server: http://download.microsoft.com/download/winmediatech40/ Update/4954/NT5/EN-US/WMSU4954_Win2000.EXE NOTE: Line breaks have been inserted into the above URLs for readability 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 MS00-013, http://www.microsoft.com/technet/security/bulletin/fq00-013.asp. - Microsoft Knowledge Base (KB) article Q253943, Misordered Windows Media Services Handshake Vulnerability, http://www.microsoft.com/technet/support/kb.asp?ID=253943 - Microsoft TechNet Security Web site, http://www.microsoft.com/technet/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 thanks Kit Knox for reporting this issue to us and working with us to protect customers. Revisions ========= - February 23, 2000: 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) 2000 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.