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Microsoft Security Bulletin (MS00-003)

Patch Available for 'Spoofed LPC Port Request' Vulnerability

Originally Posted: January 12, 2000

Summary

Microsoft has released a patch that eliminates a security vulnerability in Microsoft® Windows NT® 4.0. The vulnerability could allow a user logged onto a Windows NT 4.0 machine from the keyboard to become an administrator on the machine.

Frequently asked questions regarding this vulnerability can be found at http://www.microsoft.com/technet/security/bulletin/fq00-003.mspx

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General Information

Issue

LPC Ports is a facility that allows LPC calls on a machine. One of the functions in the LPC Ports API set enables, by design, a server thread to impersonate a client thread on the same machine. However, a flaw in the validation portion of the function would allow a malicious user to create both the client and server threads, and manipulate the impersonation request to allow it to run in the context of any desired user on the local machine, including the System itself.

The primary risk from this vulnerability is that a malicious user could exploit this vulnerability to gain additional privileges on the local machine. However, it also could be used to cause audit logs to indicate that certain actions were taken by another user. A malicious user would require the ability to log onto the target machine interactively and run arbitrary programs in order to exploit this vulnerability, and as a result, workstations and terminal servers would be at greatest risk.

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

Vulnerability Identifier: CVE-2000-0070

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Patch Availability

Microsoft Windows NT 4.0 Workstation, Server and Server, Enterprise Edition:

•	Intel: http://www.microsoft.com/Downloads/details.aspx?displaylang=en&FamilyID=0D28E8DC-576F-445A-A88B-6FB48AE82057
•	Alpha: http://www.microsoft.com/Downloads/details.aspx?displaylang=en&FamilyID=9CF26561-8862-4948-BE11-E5BBC10A0919

Microsoft Windows NT 4.0 Server, Terminal Server Edition:

•	This vulnerability is eliminated in Service Pack 6 for Windows NT 4.0 Server, Terminal Server Edition NOTE: Additional security patches are available at the Microsoft Download Center

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More Information

Please see the following references for more information related to this issue.

•

Microsoft Security Bulletin MS00-003: Frequently Asked Questions, http://www.microsoft.com/technet/security/bulletin/fq00-003.mspx

•

Microsoft Knowledge Base (KB) article 247869, Local Procedure Call may Permit Unauthorized Account Usage, http://support.microsoft.com/default.aspx?scid=kb;en-us;247869.

(Note: It may take 24 hours from the original posting of this bulletin for the KB article to be visible.)

•

Microsoft Security web site, http://www.microsoft.com/technet/security/default.mspx.

Obtaining Support on this Issue

This is a fully supported patch. Information on contacting Microsoft Technical Support is available at http://support.microsoft.com/contactussupport/?ws=support.

Acknowledgments

Microsoft thanks Bindview's RAZOR Security Team (www.bindview.com) for reporting this issue to us and working with us to protect customers.

Revisions

•	January 13, 2000: Bulletin Created.

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