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Security Bulletin 9203                  DISA Defense Communications System
February 4, 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-9203).
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                        REGISTRATION OF TAC USERS

      On 21 October 91, the Defense Information Systems Agency
      (DISA) published DDN Security Bulletin 9120, which discussed a
      problem with the timeliness of TAC users being re-registered
      with the Network Information Center (NIC).  This problem
      surfaced as a result of MILNET hosts being deconfigured and
      moved behind concentrators/gateways.  In Security Bulletin
      9120, the 15th of December had been set as the date the NIC
      was to terminate network access to all TAC users utilizing
      TAC cards registered to deconfigured hosts that had previously
      been direct-connected to the DDN.

      The purpose of this bulletin is to advise all concerned that
      the 15 December 91 termination date has been extended.  The
      reason for this decision is simple--there was not enough
      time to clear the logjam of users requiring re-registration
      processing both at the MILDEP level and at the NIC.  The
      process of re-registering TAC users who now fall behind
      concentrators/gateways had become a difficult and convoluted
      problem.  However, DISA and the Military Departments have had
      several meetings on this issue and have come to agreement on
      how to solve the problem long-term.  Therefore, once new
      registration procedures are implemented and re-registration
      is moving smoothly, a new termination date for TAC cards
      issued under the "old" deconfigured hosts will be set.
      This will probably occur within the next few months and will
      be done in conjunction with the annual re-registration 
      process.

      If there are any questions, please contact Major Boyd at
      Comm (703) 692-7580 or DSN 222-7580, e-mail to SCC@nic.ddn.mil.