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>>                                                      CERT-NL, 01-Mar-2000 <<
>> All CERT-NL information has been moved to http://cert.surfnet.nl.  Links  <<
>> to CERT-NL information contained in this advisory are therefore outdated. <<
>>                                                                           <<
>> CERT-NL also has stopped the CERT-CC-Mirror service.  Due to this the     <<
>> links to the CERT-CC mirror are obsolete. Visit the CERT-CC site for the  <<
>> complete CERT-CC advisory texts:                     http://www.cert.org  <<
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Security Advisory                                                       CERT-NL
===============================================================================
Author/Source : CERT-NL                                     Index  :    S-92-10
Distribution  : SURFnet Constituency                        Page   :          1
Classification: External                                    Version:      final
Subject       : AIX crontab Vulnerability        Date   :  26-may-92
===============================================================================

CERT-NL (SURFnet Computer Emergency Response Team) has received
information concerning a security problem in AIX crontab.

CERT-NL wishes to thank CERT/CC for bringing this to our attention.

===========================================================================
CA-92:10                        CERT Advisory
                                May 26, 1992
                          AIX crontab Vulnerability

- ---------------------------------------------------------------------------

The Computer Emergency Response Team/Coordination Center (CERT/CC) has
received information concerning a vulnerability in crontab(1) in version 3.2
of IBM's AIX operating system.

IBM is aware of this problem and a fix is available as apar number "ix26997"
for AIX version 3.2.  The version information for the patched /usr/bin/crontab
is shown in the following what(1) output:

% what /usr/bin/crontab
04 1.23 com/cmd/cntl/cron/crontab.c, cmdcntl, bos320, 9218320f 4/8/92 11:50:42
07 1.8  com/cmd/cntl/cron/permit.c, bos, bos320 4/25/91 17:16:59
11 1.15  com/cmd/cntl/cron/cronsub.c, bos, bos320 8/18/91 20:42:32
06 1.9  com/cmd/cntl/cron/funcs.c, bos, bos320 6/8/91 21:22:40

If your crontab contains older modules than the above output indicates, we
suggest that you install the fix.

- ---------------------------------------------------------------------------

I.   Description

     The distributed version of /usr/bin/crontab contains a security
     vulnerability.
     

II.  Impact

     Local users can gain unauthorized root access to the system.


III. Solution

      The CERT/CC suggests that sites install the fix that IBM has made
      available.  As an interim step, we suggests that sites prevent all
      non-root users from running /usr/bin/crontab by removing (or renaming)
      the /var/adm/cron/cron.allow and /var/adm/cron/cron.deny files.

      - Obtain the fix from IBM Support.

           1. To order from IBM call 1-800-237-5511 and ask
              that the fix be shipped.  Patches may be obtained
              outside the U.S. by contacting your local IBM
              representative.

           2. If you are on the Internet, use anonymous ftp to obtain
              the fix from software.watson.ibm.com (129.34.139.5).

              Patch           Filename                Checksum
              AIX 3.2         pub/aix3/cronta.tar.Z   02324   154

              The patch must be retrieved using binary mode.

      - Install the fix following the instructions in the README file.

- ---------------------------------------------------------------------------
The CERT/CC would like to thank Fuat Baran of Advanced Network & Services,
Inc. for bringing this security vulnerability to our attention and IBM for
their quick response to this problem.
- ---------------------------------------------------------------------------

If you believe that your system has been compromised, contact CERT/CC or
your representative in FIRST (Forum of Incident Response and Security Teams).

Internet E-mail: cert@cert.org
Telephone: 412-268-7090 (24-hour hotline)
           CERT/CC personnel answer 7:30 a.m.-6:00 p.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, information about FIRST representatives, and other
information related to computer security are available for anonymous ftp
from cert.org (192.88.209.5).

==============================================================================
CERT-NL is the Computer Emergency Response Team for SURFnet customers. SURFnet
is the Dutch network for educational, research and related institutes. CERT-NL
is a member of the Forum of Incident Response and Security Teams (FIRST).

All CERT-NL material is available under:
  http://cert.surfnet.nl/

In case of computer or network security problems please contact your local
CERT/security-team or CERT-NL  (if your institute is NOT a SURFnet customer
please address the appropriate (local) CERT/security-team).

CERT-NL is one/two hour(s) ahead of UTC (GMT) in winter/summer,
i.e. UTC+0100 in winter and UTC+0200 in summer (DST).

   Email:     cert-nl@surfnet.nl     ATTENDED REGULARLY ALL DAYS
   Phone:     +31 302 305 305        BUSINESS HOURS ONLY
   Fax:       +31 302 305 329        BUSINESS HOURS ONLY
   Snailmail: SURFnet bv
              Attn. CERT-NL
              P.O. Box 19035
              NL - 3501 DA  UTRECHT
              The Netherlands

NOODGEVALLEN:    06 22 92 35 64      ALTIJD BEREIKBAAR
EMERGENCIES : +31 6 22 92 35 64      ATTENDED AT ALL TIMES
CERT-NL'S EMERGENCY PHONENUMBER IS ONLY TO BE USED IN CASE OF EMERGENCIES:
THE SURFNET HELPDESK OPERATING THE EMERGENCY NUMBER HAS A *FIXED*
PROCEDURE FOR DEALING WITH YOUR ALERT AND WILL IN REGULAR CASES RELAY IT
TO CERT-NL IN AN APPROPRIATE MANNER. CERT-NL WILL THEN CONTACT YOU.
===============================================================================

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