***********************************************************************
DDN Security Bulletin 90-08      DCA DDN Defense Communications System
7 May 90                Published by: DDN Security Coordination Center
                                     (SCC@NIC.DDN.MIL)  (800) 235-3155

                        DEFENSE  DATA  NETWORK
                          SECURITY  BULLETIN

The DDN  SECURITY BULLETIN  is distributed  by the  DDN SCC  (Security
Coordination Center) under  DCA 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  [192.67.67.20]
using login="anonymous" and password="guest".  The bulletin pathname is
SCC:DDN-SECURITY-yy-nn (where "yy" is the year the bulletin is issued
and "nn" is a bulletin number, e.g. SCC:DDN-SECURITY-90-01).
**********************************************************************

                     UNISYS U5000 /etc/passwd PROBLEM

+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
!                                                                       !
!     The following important  advisory was  issued by the Computer     !
!     Emergency Response Team (CERT)  and is being relayed unedited     !
!     via the Defense Communications Agency's Security Coordination     !
!     Center  distribution  system  as a  means  of  providing  DDN     !
!     subscribers with useful security information.                     !
!                                                                       !
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +

CA-90-03                       CERT Advisory
                                May 7, 1990
                    Unisys U5000 /etc/passwd problem


The CERT/CC has recently verified several reports of unauthorized access 
to Internet connected Unisys systems.  The intruder(s) gained access to 
these systems by logging into vendor supplied default accounts; accounts 
that had not been given passwords by the systems' owners.  

Gary Garb, Corporate Computer Security Officer for Unisys Corporation, 
states: 

 "The Unisys U5000 series UNIX systems are delivered with a number of
 system logins.  The logins are NOT password protected when the
 customer receives the system.  Unless the customer secures these logins,
 the system is vulnerable to unauthorized access."

 "A complete list of these logins can be found in the /etc/passwd file.
 Each login is described by one record in /etc/passwd which contains a 
 number of fields separated by colons.  The second field normally would
 contain the encrypted password.  The system logins will initially have
 a null second field (indicated by two adjacent colons) in their descriptive
 records in /etc/passwd."

 "The U5000/80/85/90/95 System V Administration Guide, Volume 1 (UP13679)
 begins with a chapter on "System Identification and Security".  On page 1-2
 it states, "All logins should have passwords ... Logins that are not needed
 should be either removed (by deleting from /etc/passwd) or blocked (by 
 locking the login as described in the section "Locking Unused Logins" on
 page 1-8).  The Guide contains complete instructions on controlling logins
 and passwords."

 "It is the user's (system administrator's) responsibility to thoroughly
 read the Guide and to ensure the security of the system.  *Securing the 
 login entries should be of the highest priority and should be accomplished
 before anyone else has access to the system.*"

The CERT/CC urges administrators of Unisys systems, as well as administrators 
of systems provided by other vendors,  to check their systems and insure all 
accounts are protected by passwords; passwords that are different from the 
default passwords provided by the vendor. 

Questions regarding the security aspects of Unisys systems should be directed 
to:
   Gary Garb, Corporate Security Officer
   Unisys Corporation
   (215) 986-4038

-------
Dan Farmer
Computer Emergency Response Team (CERT)
Software Engineering Institute
Carnegie Mellon University
Pittsburgh, PA 15213-3890

Internet: cert@cert.sei.cmu.edu
Telephone: 412-268-7090 24-hour hotline: CERT personnel answer
           7:30a.m.-6:00p.m. EST, on call for
           emergencies other hours.

Past advisories and other information are available for anonymous ftp
From cert.sei.cmu.edu (128.237.253.50).