From secnotif@MICROSOFT.COM Wed Aug 11 18:48:44 1999 From: Microsoft Product Security Resent-From: mea culpa To: MICROSOFT_SECURITY@ANNOUNCE.MICROSOFT.COM Resent-To: jericho@attrition.org Date: Wed, 11 Aug 1999 10:44:42 -0700 Subject: Microsoft Security Bulletin (MS99-029) 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 (MS99-029) -------------------------------------- Patch Available for "Malformed HTTP Request Header" Vulnerability Originally Posted: August 11, 1999 Summary ======= Microsoft has released a patch that eliminates a vulnerability in web server products that use Microsoft(r) Internet Information Server 4.0 as their web engine. The vulnerability could be used to mount denial of service attacks against the web server. Frequently asked questions regarding this vulnerability can be found at http://www.microsoft.com/security/bulletins/MS99-029faq.asp Issue ===== If multiple HTTP requests containing specially-malformed headers are sent to an affected server, IIS may consume all memory on the server. If this happens, IIS would be unable to service requests until either the clients that issued the requests were closed, or the IIS service were stopped and restarted. Once either of these actions have occurred, normal service would be restored. Affected Software Versions ========================== - Microsoft Internet Information Server 4.0 - Microsoft Site Server 3.0 - Microsoft Site Server 3.0, Commerce Edition - Microsoft Commerce Internet Server 2.0 and 2.5 Patch Availability ================== - X86 version: ftp://ftp.microsoft.com/bussys/iis/iis-public/fixes /usa/security/hdbrk-fix/x86 - Alpha version: ftp://ftp.microsoft.com/bussys/iis/iis-public/fixes /usa/security/hdbrk-fix/alpha NOTE: Line breaks have been inserted in the above URLs for readability. More Information ================ Please see the following references for more information related to this issue. - Microsoft Security Bulletin MS99-029: Frequently Asked Questions, http://www.microsoft.com/security/bulletins/MS99-029faq.asp. - Microsoft Knowledge Base (KB) article Q238349, Specially-Malformed Header in HTTP Request Creates Denial of Service, http://support.microsoft.com/support/kb/articles/q238/3/49.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 Nobuo Miwa of the LAC SNS team for bringing this issue to our attention and working with us to alert customers about it. Revisions ========= - August 11, 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. ******************************************************************* 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.