IBM-ERS Security Vulnerability Alert: IBM AIX 4.3.x: Remote buffer overflow in ftp daemon

IBM-ERS Security Vulnerability Alert: IBM AIX 4.3.x: Remote buffer overflow in ftp daemon

Post by David A. Curr » Thu, 30 Sep 1999 04:00:00



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                           EMERGENCY RESPONSE SERVICE
                          SECURITY VULNERABILITY ALERT

29 September 1999 11:30 GMT                      Number:
ERS-SVA-E01-1999:004.1
===============================================================================
                           VULNERABILITY SUMMARY

VULNERABILITY:    Remote buffer overflow in ftpd daemon.

PLATFORMS:        IBM AIX(r) 4.3.x

SOLUTION:         Apply the fixes listed below.

THREAT:           Remote users can become root.

==============================================================================
                           DETAILED INFORMATION

I.  Description

A buffer overflow vulnerability has been found in the AIX 4.3.x ftpd
daemon that allows remote attackers to gain root access.  Example
exploit code has been publically released.

II.  Solutions

  A.  How to alleviate the problem

      A temporary fix is available via anonymous ftp from:

         ftp://aix.software.ibm.com/aix/efixes/security/ftpd.tar.Z

      Filename     sum                md5
      =================================================================
      ftpd         02584   147        4577818c9c95b47ffc915ab750f36bd3

      This temporary fix has not been fully regression tested.  Use the
      following steps (as root) to install the temporary fix:

      1. Uncompress and extract the fix.

         # uncompress < ftpd.tar.Z | tar xf -
         # cd ftpd

      2. Replace the vulnerable ftpd.

         # mv /usr/sbin/ftpd /usr/sbin/ftpd.before_security_fix
         # chown root.system /usr/sbin/ftpd.before_security_fix
         # chmod 0 /usr/sbin/ftpd.before_security_fix
         # cp ./ftpd /usr/sbin/ftpd
         # chown root.system /usr/sbin/ftpd
         # chmod 4554 /usr/sbin/ftpd

  B.  Official fix

      IBM is working on the following fixes which will be available
soon.

         AIX 4.2.x and earlier:  not vulnerable
         AIX 4.3.x:  IY04477

III. Obtaining Fixes

IBM AIX APARs may be ordered using Electronic Fix Distribution (via the
FixDist program), or from the IBM Support Center.  For more information
on FixDist, and to obtain fixes via the Internet, please reference

   http://techsupport.services.ibm.com/support/rs6000.support/downloads

or send electronic mail to "aixs...@austin.ibm.com" with the word
"FixDist" in the "Subject:" line.  To facilitate ease of ordering all
security related APARs for each AIX release, security fixes are
periodically bundled into a cumulative APAR.  For more information on
these cumulative APARs including last update and list of individual
fixes, send electronic mail to "aixs...@austin.ibm.com" with the word
"subscribe Security_APARs" in the "Subject:" line.

IV.  Contact Information

Comments regarding the content of this announcement can be directed to
your local IBM support center or to:

   security-al...@austin.ibm.com

To request the PGP public key that can be used to encrypt new AIX
security vulnerabilities, send email to security-al...@austin.ibm.com
with a subject of "get key".

If you would like to subscribe to the AIX security newsletter, send a
note to aixs...@austin.ibm.com with a subject of "subscribe Security".
To cancel your subscription, use a subject of "unsubscribe Security".
To see a list of other available subscriptions, use a subject of
"help".

IBM and AIX are a registered trademark of International Business
Machines Corporation.  All other trademarks are property of their
respective holders.

===============================================================================

IBM's Internet Emergency Response Service (IBM-ERS) is a
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Visit the site for information about the service, copies of security
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Copyright 1999 International Business Machines Corporation.

The information in this document is provided as a service to customers
of
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Machines
Corporation, nor any of its employees, makes any warranty, express or
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The material in this security alert may be reproduced and distributed,
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