DOCUMENT:Q222159 16-MAY-2002 [winnt] TITLE :Symbolic Link Case Sensitivity Exploit Bypasses System Security PRODUCT :Microsoft Windows NT PROD/VER:winnt:4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4 OPER/SYS: KEYWORDS:kbWinNT400sp5fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server versions 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3, 4.0 SP4 - Microsoft Windows NT Workstation versions 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3, 4.0 SP4 - Microsoft Windows NT Server, Enterprise Edition versions 4.0, 4.0 SP4 ------------------------------------------------------------------------------- SYMPTOMS ======== When you modify the "\??" object folder's symbolic link table by substituting a different case (upper versus lower) letter in the table to point to a different device associated with a disk drive alias, it may be possible to bypass typical Windows NT security and allow any user to acquire administrator privileges. RESOLUTION ========== To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the individual software update. For information on obtaining the latest service pack, please go to: - http://www.microsoft.com/windows/servicepacks/ -or- - Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack For information on obtaining the individual software update, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web: http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS Once you have installed the Windows NT 4.0 service pack, it is necessary to enable base system object restrictions to prevent the use of this security exploit. To do this: 1. Click Start, click Run, type "regedt32" (without the quotation marks), and then click OK. 2. On the Windows menu, click "HKEY_LOCAL_ MACHINE on Local Machine". 3. Double-click the \System\CurrentControlSet\Control\Session Manager folder. 4. Double-click the "ProtectionMode" (without the quotation marks) value, type "1" (without the quotation marks), and then click OK. 5. Quit Registry Editor, and then restart the computer. STATUS ====== Microsoft has confirmed this to be a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows NT 4.0 Service Pack 5. Additional query words: ====================================================================== Keywords : kbWinNT400sp5fix Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTW400sp4 kbWinNTW400sp3 kbWinNTW400sp2 kbWinNTW400sp1 kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400sp4 kbWinNTSEnt400 kbWinNTS400sp4 kbWinNTS400sp3 kbWinNTS400sp2 kbWinNTS400sp1 kbWinNTS400search kbWinNTS400 Version : winnt:4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4 Hardware : ALPHA x86 Issue type : kbbug Solution Type : kbfix ============================================================================= 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. Copyright Microsoft Corporation 2002.