Microsoft Security Bulletin (MS00-007) -------------------------------------- Patch Available for "Recycle Bin Creation" Vulnerability Originally Posted: February 1, 2000 Summary ======= Microsoft has released a patch that eliminates a security vulnerability in Microsoft(r) Windows NT 4.0. Under a very daunting set of conditions, a malicious user could create, delete or modify files in the Recycle Bin of another user who shared the machine. In most cases, the vulnerability would not allow the malicious user to read the files unless they already had read permission to do so. Frequently asked questions regarding this vulnerability and the patch can be found at http://www.microsoft.com/technet/security/bulletin/fq00-007.asp Issue ===== The Windows NT Recycle Bin for a given user maps to a folder, whose name is based on the owner's SID. The folder is created the first time the user deletes a file, and the owner is given sole permissions to it. However, if a malicious user could create the folder before the bona fide one were created, he or she could assign any desired permissions to it. This would allow him or her to create, modify or delete files in the Recycle Bin, but in most cases would not enable them to read files unless he or she already were able to. There are several significant limitations that would make it difficult to exploit this vulnerability: - The malicious user would need to create the bogus Recycle Bin before the user's bona fide one were created. - The malicious user would need to share a machine with the other user. The vulnerability would only enable the malicious user to take action against the Recycle Bin on the particular machine, and the particular partition, that was attacked. - The malicious user could add files to the Recycle Bin, but this vulnerability would not allow him or her to induce the other user to retrieve them. Affected Software Versions ========================== - Microsoft Windows NT Workstation 4.0 - Microsoft Windows NT Server 4.0 - Microsoft Windows NT Server 4.0, Enterprise Edition Patch Availability ================== - Intel: http://www.microsoft.com/downloads/release.asp?ReleaseID=17606 - Alpha: http://www.microsoft.com/downloads/release.asp?ReleaseID=17607 NOTE: This patch only needs to be applied to Windows NT systems using NTFS file volumes. The vulnerability is moot for FAT volumes, as FAT provides no per-user data separation by design. See the FAQ for more information. 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 MS00-007, http://www.microsoft.com/technet/security/bulletin/fq00-007.asp. - Microsoft Knowledge Base (KB) article Q248399, Shared Workstation Setup may Permit Access to Recycle Bin Files. (A link will be posted here as soon as the article is available, in approximately 24 hours) - Microsoft TechNet Security web site. 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 Arne Vistrom and Nobuo Miwa for reporting this issue to us and working with us to protect customers. Revisions ========= - February 1, 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. 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