L-026: Microsoft Windows NT "Registry Permissions" Vulnerability

PROBLEM:       Three registry keys: (1) SNMP Parameters, (2) RAS
               Administration, and (3) MTS Package Administration have default
               permissions that are inappropriately set.
PLATFORM:      Microsoft Windows NT 4.0 Microsoft Windows NT 4.0 Server
               Microsoft Windows NT 4.0 Server, Enterprise Edition Microsoft
               Windows NT 4.0 Server, Terminal Server Edition
DAMAGE:        The default permissions could allow a malicious user to gain
               additional privileges on an affected machine.
SOLUTION:      Apply the patch indicated below.
VULNERABILITY  The risk is medium. Allows elevated privileges, but must have
ASSESSMENT:    prior access.


[****** Start of Microsoft Security Bulletin ******]

Microsoft Security Bulletin (MS00-095)

Tool Available for "Registry Permissions" Vulnerability
Originally posted: December 06, 2000

Summary

Microsoft has released a tool that corrects the permissions on several
registry values in Microsoft® Windows NT® 4.0. The default permissions
could allow a malicious user to gain additional privileges on an affected
machine.

Frequently asked questions regarding this vulnerability and the patch can
be found at http://www.microsoft.com/technet/security/bulletin/fq00-095.asp

Issue

Three registry keys have default permissions that are inappropriately
loose. The keys, and the risk they pose, are as follows:

The "SNMP Parameters" key,

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SNMP\Parameters,
provides the SNMP community name and SNMP management station
identifiers, if they exist. Reading this information would enable a
malicious user to pose as a bona fide SNMP manager for any community the
affected machine belonged to. (In actuality, though, the same
information could be obtained by monitoring network traffic). Changing
this information would enable her to create a community consisting
solely of her local machine, as a way of gaining management privileges
on it. SNMP is not installed on Windows NT 4.0 machines by default.

The "RAS Administration" key,

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RAS,
provides a way to install third-party RAS products that work with the
Windows NT native RAS service. By changing one of the values in this
key, it would be possible for a malicious user to specify code of her
choice as a third-party management tool. The code would then run in the
LocalSystem security context. Although it might be possible to make the
needed registry changes remotely, the malicious user’s code would need
to reside on the affected machine itself. RAS is not installed on
Windows NT 4.0 machines by default.

The "MTS Package Administration" key,

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Transaction Server\Packages,
includes information about which users are allowed to install and change
MTS packages. By adding herself as an MTS manager, a malicious user
could gain the ability to add, delete or change MTS packages. Although
it might be possible in some cases to make the needed registry changes
remotely, the malicious user would still need the ability to log onto
the affected machine interactively in order to exercise her new
privileges. MTS is not installed on Windows NT 4.0 machines by default.

In addition to correcting the permissions on these keys, the tool also
changes the permissions on several other keys that have previously been
discussed. Specifically, the tool makes all the changes discussed in
Microsoft Security Bulletins MS00-008 and MS00-024.

Affected Software Versions
    Microsoft Windows NT 4.0
    Microsoft Windows NT 4.0 Server
    Microsoft Windows NT 4.0 Server, Enterprise Edition
    Microsoft Windows NT 4.0 Server, Terminal Server Edition

Patch Availability

http://www.microsoft.com/Downloads/Release.asp?ReleaseID=24501

Note: The version of the tool in this bulletin also includes all changes
discussed in Security Bulletins MS00-008 and MS00-024.

Note: This tool may be run on machines running Windows NT 4.0 Service
Packs 5 and 6a.

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 MS00-095,
http://www.microsoft.com/technet/security/bulletin/fq00-095.asp

Microsoft Security Bulletin MS00-008,
http://www.microsoft.com/technet/security/bulletin/ms00-008.asp

Microsoft Security Bulletin MS00-024, http://www.microsoft.com/technet/security/bulletin/ms00-024

Microsoft Knowledge Base article Q265714 discusses the "SNMP Parameters"
vulnerability and will be available soon.

Microsoft Knowledge Base article Q267861 discusses the "RAS
Administration" vulnerability and will be available soon.

Microsoft Knowledge Base article Q267864 discusses the "MTS Package
Administration" vulnerability 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  the following people for working with us to protect
customers:
        Chris Anley of @stake for reporting the "SNMP Parameters" vulnerability.
        Milan Dadok for reporting the "RAS Administration" vulnerability.
        Glenn Larsson for reporting the "MTS Package Administrator"
        vulnerability.

Revisions
    December 06, 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.

[****** End of Microsoft Security Bulletin ******]

    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/
                     http://ciac.llnl.gov
                     (same machine -- either one will work)
    Anonymous FTP:   ftp.ciac.org
                     ciac.llnl.gov
                     (same machine -- either one will work)