_____________________________________________________
             The Computer Incident Advisory Capability
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        _____________________________________________________
                         Information Bulletin

March 26, 1991, 1330 PST                                     Number B-20

                    Patch Available for SunOS in.telnetd
________________________________________________________________________
PROBLEM:  SunOS versions 4.0.3 through 4.1.1 in.telnetd exhibits may
          send output to an authorized user.  
PLATFORM: All Sun3 and Sun4 computers running SunOS 4.0.3, 4.1 or
          4.1.1.  
DAMAGE:   May allow unauthorized access to the system.
SOLUTIONS:  Patch/update available from Sun.  
IMPACT OF PATCH:  Vulnerability eliminated.  No other side-effects
          reported.
_______________________________________________________________________
     Critical Information about in.telnetd Patch

Sun Microsystems has recently announced the availability of a new patch
for the utility in.telnetd (the daemon that controls the remote login
program, telnet).  If not patched this utility may allow unauthorized
access to systems.  The patch is available from Sun Microsystems as
Patch ID# 100125-02 (this number is required to order this patch from
the Sun Answer Center).  This patch is also available via anonymous ftp
at uunet.uu.net (IP# 192.48.96.2) in the file
sun-dist/100125-02.tar.Z.  If you obtain the patch using anonymous ftp,
no additional installation instructions are necessary.  If you obtain
the patch in some other manner (e.g., from CIAC), we suggest that you
use the following installation procedure:

1.  Log in as root on the system to be repaired.

2.  Disable the flawed version of in.telnetd with the following 
commands:

  # mv /usr/etc/in.telnetd /usr/etc/in.telnetd.FCS
  # chmod 600 /usr/etc/in.telnetd.FCS

3.  Obtain the patch file 100125-02.tar.Z (either from Sun or a trusted 
anonymous FTP site such as uunet.uu.net).

4.  Uncompress the patch file:

  # uncompress 100125-02.tar.Z

5.      Extract the patch file appropriate to your architecture (either
3, 3x, 4, or 4c -- contact your Sun representative if you do not know
which architecture you have)

  # tar xf 100125-02.tar {architecture}/in.telnetd
  where {architecture} is one of 3, 3x, 4, or 4c.

6.      Copy the patch file to the appropriate directory, and set the
ownership and permissions of the utility:

  # cp {architecture}/in.telnetd /usr/etc/in.telnetd
  # chown root.staff /usr/etc/in.telnetd
  # chmod 755 /usr/etc/in.telnetd

7.  Kill any existing telnet processes that may be running.

  # ps ugax | grep in.telnetd
  # kill -9 ####
  where #### is the number of each in.telnetd process found in
  the previous command.  Please note that this command may
  disrupt ongoing sessions of users attempting to use the
  system.  As an alternative to this step, you may consider
  rebooting the computer, allowing time for all current users to
  log out.

Once you have verified that the new version of telnet is operational,
it is advisable to delete the unpatched version of the utility
(/usr/etc/in.telnetd.FCS) to prevent its unauthorized use.

For additional information or assistance, please contact CIAC:   
 
  Tom Longstaff
  (415) 423-4416 or (FTS) 543-4416

  Call CIAC at (415) 422-8193 or (FTS) 532-8193 or 
        send e-mail to ciac@cheetah.llnl.gov.  
    
  Send FAX messages to:  (415) 423-0913 or (FTS) 543-0913

Sun Microsystems provided information contained in this bulletin.  This
document was prepared as an account of work sponsored by an agency of
the United States Government. Neither the United States Government nor
the University of California nor any of their employees, makes any
warranty, express or implied, or assumes any legal liability or
responsibility for the accuracy, completeness, or usefulness of any
information, apparatus, product, or process disclosed, or represents
that its use would not infringe privately owned rights. Reference
herein to any specific commercial products, process, or service by
trade name, trademark, manufacturer, or otherwise, does not necessarily
constitute or imply its endorsement, recommendation or favoring by the
United States Government or the University of California. The views and
opinions of authors expressed herein do not necessarily state or
reflect those of the United States Government or the University of
California, and shall not be used for advertising or product
endorsement purposes.