From secnotif@MICROSOFT.COM Thu Apr 13 06:42:03 2000 From: Microsoft Product Security Resent-From: mea culpa To: MICROSOFT_SECURITY@ANNOUNCE.MICROSOFT.COM Resent-To: jericho@attrition.org Date: Wed, 12 Apr 2000 20:57:36 -0700 Subject: Microsoft Security Bulletin (MS00-024) 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 (MS00-024) - -------------------------------------- Tool Available for "OffloadModExpo Registry Permissions" Vulnerability Originally Posted: April 12, 2000 Summary ======= Microsoft has released a tool that installs tighter permissions on a Windows NT(r) 4.0 registry key. The default permissions could allow a malicious user who can interactively log onto a Windows NT 4.0 machine to compromise the cryptographic keys of other users who subsequently log onto the same machine. Frequently asked questions regarding this vulnerability and the patch can be found at http://www.microsoft.com/technet/security/bulletin/fq00-024.asp Issue ===== This vulnerability involves a registry key used by the CryptoAPI Base CSPs to specify the driver DLL for a hardware accelerator. By design, such a DLL would have access to users' public and private keys. Although only administrators should have permission to add such a DLL, the permissions on the key actually would allow any user who could interactively log onto the machine to do so. By writing a bogus DLL and installing it, a malicious user could compromise the keys of other users who subsequently used the machine. The machines primarily at risk would be workstations and terminal servers. If normal security recommendations are followed, normal users will not be allowed to interactively log onto domain controllers, web servers, database servers, ERP servers, and other security-critical machines. Windows NT auditing could be used to determine who changed the key's value. A tool is available that resets the permissions on the affected key to the correct default values. In addition, it incorporates the functionality of the tool provided in Microsoft Security Bulletin MS00-008. Affected Software Versions ========================== - Microsoft Windows NT 4.0 Workstation - Microsoft Windows NT 4.0 Server - Microsoft Windows NT 4.0 Server, Enterprise Edition - Microsoft Windows NT 4.0 Server, Terminal Server Edition NOTE: Windows 2000 is not affected by this vulnerability. Patch Availability ================== - X86: http://www.microsoft.com/Downloads/Release.asp?ReleaseID=20330 - Alpha: http://www.microsoft.com/Downloads/Release.asp?ReleaseID=20331 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 MS00-024, http://www.microsoft.com/technet/security/bulletin/fq00-024.asp - Microsoft Knowledge Base article Q259496 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 Technical Support is available at http://support.microsoft.com/support/contact/default.asp. Acknowledgments =============== Microsoft thanks Sergio Tabanelli and Banca Nazionale del Lavoro for reporting this vulnerability to us and working with us to protect customers. Revisions ========= - April 12, 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 April 12, 2000 (c) 2000 Microsoft Corporation. All rights reserved. Terms of use. -----BEGIN PGP SIGNATURE----- Version: PGP 6.0.2 iQEVAwUBOPVFrI0ZSRQxA/UrAQFU2AgAk/Alna76rgEvMbB0XJe694FeKJmS2IfK +39tf67XVIUP843o28mSl2Y4cT8cw6MXoNySOATuZeIX6VgBFNACTsCjAswmE/H8 tufDcblbDJ3AzMWQlJdPsmDHUA4CXE4bwBd8tJLGI/4D7cdxBIjMjJRNRP/lCDhW oFUqnPJad/DVcq9cFpzJsdDEMJrZnuAA044h7glJcC8MMpdG0Pwle6czrwsui0U0 3R7PrC4Kijv3R8m2q/n/nQ5eAJCOKK6EW+BT8oCBx5FH0s0O5rJPjHQbMQKmEh3b Vx8glN+QxYp0X09LqB1okH3/Kk/OHC22rKcvCqtbCfJJ6hpnw+qn4g== =jE/X -----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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