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Microsoft IIS Folder Traversal
Microsoft IIS Folder Traversal Privacy and Legal Notice


L-007: Microsoft IIS Folder Traversal

October 17, 2000 20:00 GMT
PROBLEM:       Microsoft has identified a canonical error in the Internet
               Information Server (IIS). Unicode Exploit.
PLATFORM:      Any platforms running Microsoft IIS 4.0 and 5.0
DAMAGE:        A particular type of malformed URL may allow access to files
               and folders that lie anywhere on the logical drive.
SOLUTION:      Apply appropriate patches as indicated below.

VULNERABILITY Risk is MEDIUM. The vulnerability affects system security and is ASSESSMENT: publicly known. Patches should be applied as soon as possible.
[****** Start of Microsoft Security Bulletin ******] Microsoft Security Bulletin (MS00-078) --------------------------------------- Patch Available for "Web Server Folder Traversal" Vulnerability Originally posted: October 17, 2000 Summary ======= Microsoft has released a patch that eliminates a security vulnerability in Microsoft(r) IIS 4.0 and 5.0. The vulnerability could potentially allow a visitor to a web site to take a wide range of destructive actions against it, including running programs on it. This vulnerability is eliminated by the patch that accompanied Microsoft Security Bulletin MS00-057. Customers who have applied that patch are already protected against the vulnerability and do not need to take additional action. Microsoft strongly urges all customers using IIS 4.0 and 5.0 who have not already done so to apply the patch immediately. Frequently asked questions regarding this vulnerability and the patch can be found at http://www.microsoft.com/technet/security/bulletin/fq00-078.asp Issue ===== Due to a canonicalization error in IIS 4.0 and 5.0, a particular type of malformed URL could be used to access files and folders that lie anywhere on the logical drive that contains the web folders. This would potentially enable a malicious user who visited the web site to gain additional privileges on the machine - specifically, it could be used to gain privileges commensurate with those of a locally logged-on user. Gaining these permissions would enable the malicious user to add, change or delete data, run code already on the server, or upload new code to the server and run it. The request would be processed under the security context of the IUSR_machinename account, which is the anonymous user account for IIS. Within the web folders, this account has only privileges that are appropriate for untrusted users. However, it is a member of the Everyone and Users groups and, as a result, the ability of the malicious user to access files outside the web folders becomes particularly significant. By default, these groups have execute permissions to most operating system commands, and this would give the malicious user the ability to cause widespread damage. Customers who have proactively removed the Everyone and Users groups from permissions on the server, or who are hosting the web folders on a different drive from the operating system, would be at significantly less risk from the vulnerability. Microsoft strongly recommends that all customers running IIS 4.0 or 5.0 immediately apply the patch for this vulnerability. This patch was originally released in August 2000 as a fix for a completely different vulnerability (discussed in Microsoft Security Bulletin MS00-057), and customers who have already applied it do not need to take any additional action. Affected Software Versions ========================== - Microsoft IIS 4.0 - Microsoft IIS 5.0 Patch Availability ================== - Microsoft IIS 4.0: http://www.microsoft.com/ntserver/nts/downloads/critical/q269862 - Microsoft IIS 5.0: http://www.microsoft.com/windows2000/downloads/critical/q269862 Note: The IIS 4.0 patch can be installed on systems running Windows NT(r) 4.0 Service Packs 5 and 6a. It will be included in Windows NT 4.0 Service Pack 7. The IIS 5.0 patch can be installed on systems running either Windows(r) 2000 Gold or Service Pack 1. It will be included in Windows 2000 Service Pack 2. Note: The Download Center pages discussed above may, for the next several days, only reference the "File Permissions Canonicalization" vulnerability. However, we are updating the pages to state that it applies to both that vulnerability and this one. 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 MS00-078, http://www.microsoft.com/technet/security/bulletin/fq00-078.asp - Microsoft Security Bulletin MS00-057, Microsoft Security Bulletin http://www.microsoft.com/technet/security/bulletin/ms00-057.asp - Microsoft Knowledge Base article Q276489 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 Rain Forest Puppy for reporting this issue to us and working with us to protect customers. Revisions ========= - October 17, 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 October 17, 2000 (c) 2000 Microsoft Corporation. All rights reserved. Terms of use. [****** End of Microsoft Security Bulletin ******]

CIAC wishes to acknowledge the contributions of Microsoft for the information contained in this bulletin.
CIAC services are available to DOE, DOE Contractors, and the NIH. CIAC can be contacted at:
    Voice:          +1 925-422-8193 (7 x 24)
    FAX:            +1 925-423-8002
    STU-III:        +1 925-423-2604
    E-mail:          ciac@llnl.gov
    World Wide Web:  http://www.ciac.org/
                     (same machine -- either one will work)
    Anonymous FTP:   ftp.ciac.org
                     (same machine -- either one will work)

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