From secnotif@MICROSOFT.COM Thu Aug 10 23:13:19 2000 From: Microsoft Product Security Resent-From: mea culpa To: MICROSOFT_SECURITY@ANNOUNCE.MICROSOFT.COM Resent-To: jericho@attrition.org Date: Thu, 10 Aug 2000 11:08:48 -0700 Subject: Microsoft Security Bulletin (MS00-057) 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. ******************************** -----BEGIN PGP SIGNED MESSAGE----- Microsoft Security Bulletin (MS00-057) - -------------------------------------- Patch Available for "File Permission Canonicalization" Vulnerability Originally posted: August 10, 2000 Summary ======= Microsoft has released a patch that eliminates a security vulnerability in Microsoft(r) Internet Information Server. Under very restricted conditions, the vulnerability could allow a malicious user to gain additional permissions to certain types of files hosted on a web server. Frequently asked questions regarding this vulnerability and the patch can be found at http://www.microsoft.com/technet/security/bulletin/fq00-057.asp Issue ===== A canonicalization error can, under certain conditions, cause IIS 4.0 or 5.0 to apply incorrect permissions to certain types of files. If an affected file residing in a folder with restrictive permissions were requested via a particular type of malformed URL, the permissions actually used would be those of a folder in the file's parentage chain, but not those of the folder the file actually resides in. If the ancestor folder's permissions were more permissive than those of the correct folder, the malicious user would gain additional privileges to the affected file. The vulnerability is subject to several significant restrictions: - It only affects CGI scripts and file types that are implemented via ISAPI extensions. It does not affect static web page or non-web file types such as .exe, .doc or .bat - It only affects servers that expose a web folder structure that mirrors the physical folder structure on the server. - It does not allow arbitrary permissions to be selected, only permissions present on an ancestor folder - It provides no way to enumerate the server and locate files that could be affected by the vulnerability. Affected Software Versions ========================== - Microsoft Internet Information Server 4.0 - Microsoft Internet Information Server 5.0 Patch Availability ================== - Microsoft Internet Information Server 4.0: http://www.microsoft.com/Downloads/Release.asp?ReleaseID=23667 - Microsoft Internet Information Server 5.0: http://www.microsoft.com/Downloads/Release.asp?ReleaseID=23665 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 MS00-057, http://www.microsoft.com/technet/security/bulletin/fq00-057.asp - Microsoft Knowledge Base article Q269862 discusses this issue and will be available soon. - 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 Product Support Services is available at http://support.microsoft.com/support/contact/default.asp. Acknowledgments =============== Microsoft thanks Burt Abreu & Søren Skov of VBExplorer.com for reporting this issue to us and working with us to protect customers. Revisions ========= August 10, 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. Last Updated August 10, 2000 (c) 2000 Microsoft Corporation. All rights reserved. Terms of use. -----BEGIN PGP SIGNATURE----- Version: PGP Personal Privacy 6.5.3 iQEVAwUBOZLvrY0ZSRQxA/UrAQHewgf+Ks8c/EmNUdguRAru3xmrwYJfL5Pxkmlv RytMqC1iqTVUdUtrOoZaThB4m6WfaYDTLoiV9jJrnVHJ4t0/geoIEzUkQIw3rvY2 kVZAWS+vSG3gCOHKN/0710Go1lKCKTHhLh4vVVc9LrvXRTAYE88Med2EAKrMsRNd LG3WrWArdFTdSfwqDQ5jJ48xf+qYHK63O+Yh4MdLXjpY2Bxd6U/eHz7eIn2qhpEx BoqGpLcHN1KKmGbcTIgUzYpIXo+I10c1efVIgH9sCPEXGelOVtzFg7dFGOQjF9xo pn2XjQDnD/tyh7RodSAvyxy5zkwyMwMF+x8nNRDodACMA7F1YeC07A== =LDZS -----END PGP SIGNATURE----- ******************************************************************* You have received this e-mail bulletin as a result of your registration to the Microsoft Product Security Notification Service. 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