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Security Bulletin 9201                  DISA Defense Communications System
January 22,1992             Published by: DDN Security Coordination Center
                                      (SCC@NIC.DDN.MIL)   1-(800) 365-3642

                        DEFENSE  DATA  NETWORK
                          SECURITY  BULLETIN

The DDN  SECURITY BULLETIN is distributed  by the  DDN SCC  (Security
Coordination Center) under DISA contract as  a means of  communicating
information on network and host security exposures, fixes, &  concerns
to security & management personnel at DDN facilities.  Back issues may
be  obtained  via  FTP  (or  Kermit)  from  NIC.DDN.MIL  [192.112.36.5]
using login="anonymous" and password="guest".  The bulletin pathname is
SCC:DDN-SECURITY-yynn (where "yy" is the year the bulletin is issued
and "nn" is a bulletin number, e.g. SCC:DDN-SECURITY-9201).
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!                                                                       !
!     The following important  advisory was  issued by the Computer     !
!     Emergency Response Team (CERT)  and is being relayed unedited     !
!     via the Defense Information Systems Agency's Security             !
!     Coordination Center  distribution  system  as a  means  of        !
!     providing  DDN subscribers with useful security information.      !
!                                                                       !
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CA-92:01                        CERT Advisory
                              January 20, 1992
                     NeXTstep Configuration Vulnerability

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The Computer Emergency Response Team/Coordination Center (CERT/CC)  
has received information concerning a vulnerability in release 2 of
NeXTstep's NetInfo default configuration.  This vulnerability will
be corrected in future versions of NeXTstep.

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I.   Description

     By default, a NetInfo server process will provide information to
     any machine that requests it.


II.  Impact

     Remote users can gain unauthorized access to the network's
     administrative information such as the passwd file.


III. Solution

     Ensure that the trusted_networks property of each NetInfo domain's
     root NetInfo directory is set correctly, so that only those systems
     which should be obtaining information from NetInfo are granted
     access. The value for the trusted_networks property should be the
     network numbers of the networks the server should trust.

     Note that improperly setting trusted_networks can render your
     network unusable.

     Consult Chapter 16, "Security", of the "NeXT Network and System
     Administration" manual for release 2 for details on setting the
     trusted_networks property of the root NetInfo directory.

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The CERT/CC wishes to thank NeXT Computer, Inc. for their cooperation in
documenting and publicizing this security vulnerability.
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If you believe that your system has been compromised, contact CERT/CC via
telephone or e-mail.

Internet E-mail: cert@cert.sei.cmu.edu
Telephone: 412-268-7090 (24-hour hotline)
           CERT/CC personnel answer 7:30a.m.-6:00p.m. EST(GMT-5)/EDT(GMT-4),
           on call for emergencies during other hours.

Computer Emergency Response Team/Coordination Center (CERT/CC)
Software Engineering Institute
Carnegie Mellon University
Pittsburgh, PA 15213-3890

Past advisories and other information related to computer security are
available for anonymous ftp from the cert.sei.cmu.edu (192.88.209.5) system.