Visit our newest sister site!
Hundreds of free aircraft flight manuals
Civilian • Historical • Military • Declassified • FREE!


TUCoPS :: Unix :: Various Flavours :: ciacl123.txt

CIAC L-123 AIX libil8n Library Vulnerability




             __________________________________________________________

                       The U.S. Department of Energy
                     Computer Incident Advisory Center
                           ___  __ __    _     ___
                          /       |     /_\   /
                          \___  __|__  /   \  \___
             __________________________________________________________

                             INFORMATION BULLETIN

                       AIX libi18n Library Vulnerability

July 24, 2001 15:00 GMT                                           Number L-123
______________________________________________________________________________
PROBLEM:       There is a software vulnerability in the libi18n Library 
PLATFORM:      IBM AIX 4.3.x and 5.1
               NOTE: Fix will not be provided for versions prior to 4.3
               as these are no longer supported by IBM.  Affected customers
               are urged to upgrade to 4.3.3 at the latest maintenance level
               or to 5.1.
DAMAGE:        The "libi18n" library contains a function that is vulnerable to 
               a buffer overflow through the LANG environment variable. 
               Through the usage of the "LANG" environment variable a local 
               user can obtain root level privileges. 
SOLUTION:      Apply the temporary fix or workaround as specified by IBM. 
               IBM is working on a official patch. Read the instructions 
               regarding the 'efix' installation carefully before installing 
               the temporary fix. 
______________________________________________________________________________
VULNERABILITY  The risk is LOW. There have been no publicly reported attacks 
ASSESSMENT:    using this methodology and the usage requires local access. 
______________________________________________________________________________
LINKS: 

 PATCHES:                                                                     
                     ftp://aix.software.ibm.com/aix/efixes/security/libi18n_efix.tar.Z 
______________________________________________________________________________

[******  Begin IBM advisory ******]

IBM Global Services
Managed Security Services
Outside Advisory Redistribution

18 JUL 2001  23:47 GMT                              MSS-OAR-E01-2001:271.1
===========================================================================
The MSS Outside Advisory Redistribution is designed to provide customers of
IBM Managed Security Services with access to the security advisories
sent out by other computer security incident response teams, vendors, and
other groups concerned about security.

IBM makes no representations and assumes no responsibility for the contents
or accuracy of the advisories themselves.

IBM MSS is forwarding the following information from IBM.
Contact information for IBM is included in the forwarded text
below. Please contact them if you have any questions or need further
information.
===========================================================================
----------- Forwarded Information Starts Here.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

IBM SECURITY ADVISORY

Thu Jun 28 10:06:00 CDT 2001
===========================================================================
                           VULNERABILITY SUMMARY

VULNERABILITY:    Buffer Overflow Vulnerability in libi18n Library

PLATFORMS:        IBM AIX 4.3.x and 5.1

SOLUTION:         Apply the emergency-fixes described below, or
                  employ the workaround, also described below.

THREAT:           Malicious local user could obtain root privileges.

CERT Advisory:    NONE.

CVE candidate:    CAN-2001-0533

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

I.  Description

    AIX ships with the library "libi18n" located in the "/usr/ccs/lib"
    directory. This library contains a function that is vulnerable
    to a buffer overflow through the LANG environment variable.

    An ordinary user has the ability to set the "LANG" environment
    variable to any value they choose. When this variable is set to a
    suitably formatted string and a program is run which uses the vulnerable
    library, the program will terminate abnormally. If this program is also
    setuid root, aixterm for example, a malicious user has an opportunity
    to spawn a root shell and gain control of the machine.

II. Impact

   A malicious local user can use a well-crafted exploit code
   to gain root privileges on the attacked system, compromising the
   integrity of the system and its attached local network.

III.  Solutions

  A.  WORKAROUND

      If you do not wish to install the efix for this vulnerability
      but instead wait for the APAR that fixes it to be made
      available, you can also negate this vulnerability by making the
      "aixterm" program to be non-SUID. You must be "root" to do this.
      Ordinary users will still be able to use the program, although there
      may be unexpected side effects.

  B.  Official Fix

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

           AIX 4.3.x   -  IY20867
           AIX 5.1.0   -  IY21309

      NOTE: Fix will not be provided for versions prior to 4.3 as
      these are no longer supported by IBM. Affected customers are
      urged to upgrade to 4.3.3 at the latest maintenance level,
      or to 5.1.

  C.  How to minimize the vulnerability

    Temporary fixes for AIX 4.3.x and 5.1 systems are available.

    The temporary fixes can be downloaded via ftp from:

    ftp://aix.software.ibm.com/aix/efixes/security/libi18n_efix.tar.Z

    The efix tarball consists of a patched libi18n tarred binary which is
    compatible with both 4.3.x and 5.1.0 releases.  A copy of this Advisory
    is included in the efix tarball.

    These temporary fixes have not been fully regression tested; thus,
    IBM does not warrant the fully correct functioning of the efix.
    Customers install the efix and operate the modified version of AIX
    at their own risk.

    To proceed with efix installation:

    First, verify the MD5 cryptographic hash sums of each efix files
    you obtain from unpacking the efix tarball with those given below.
    These should match exactly; if they do not, double check the hash results
    and the download site address. If OK, contact IBM AIX Security at
    security-alert@austin.ibm.com and describe the discrepancy.

    Filename        sum             md5
    =================================================================
    libi18n.tar    34706   130      1227c815533ae2f70a0eac71c5016263

    Efix Installation Instructions:
    -------------------------------

    IMPORTANT NOTICE: Before installing the efix, you must upgrade
    to the latest maintenance level of AIX for your version of AIX.

    1. Become root, if not already done.

    2. Change to the /usr/ccs/lib directory. Make a backup copy of the
       existing libi18n.a binary, giving it a distinctive, meaningful
       name, such as "libi18n.a.original" or "libi18n.a.backup". This
       is IMPORTANT to do, so you can recover the original libi18n.a
       binary if something goes wrong during the installation of the efix!

    3. In the root ("/") directory, download, uncompress, and untar
       the efix.

       a. uncompress libi18n_efix.tar.Z
       b. tar -xvf libi18n_efix.tar

    4. You will have a tarfiles named "libi18n.tar".
       You may discard the other, unneeded tarfile.

       Untar the tarfile by executing "tar -xvf libi18n.tar".
       The efix version of libi18n will be untarred and placed
       in the proper directory.

    5. Check to be certain that the new libi18n.a library
       is assigned proper permissions, "-r--r--r--", and the ownership
       is assigned properly, "bin" and "bin".


IV. 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/rs6k/fixes.html

or send email to "aixserv@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 email to "aixserv@austin.ibm.com" with
the word "subscribe Security_APARs" in the "Subject:" line.


V.  Acknowledgments

    Many thanks go to Troy Bollinger of IBM MSSD for discovering this
    vulnerability and for demonstrating its exploitation.

VI.  Contact Information

Comments regarding the content of this announcement can be directed to:

   security-alert@austin.ibm.com

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

If you would like to subscribe to the AIX security newsletter, send a
note to aixserv@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 Managed Security Services (MSS) is a subscription-based Internet
security response service that includes computer security incident response
and management, regular electronic verification of your Internet
gateway(s), and security vulnerability alerts similar to this one that are
tailored to your specific computing environment.  By acting as an extension
of your own internal security staff, IBM MSS's team of Internet security
experts helps you quickly detect and respond to attacks and exposures
across your Internet connection(s).

As a part of IBM's Business Continuity and Recovery Service IBM's Managed
Security Services is a component of IBM Global Services Privacy and
Security Services suite of offerings.  To find out more about IBM Managed
Security Services, send an electronic mail message to
ers-sales@ers.ibm.com, or call 1-800-426-7378.

IBM MSS maintains a site on the World Wide Web at http://www.ers.ibm.com/.
Visit the site for information about the service, copies of security
alerts, team contact information, and other items.

IBM MSS uses Pretty Good Privacy* (PGP*) as the digital signature mechanism
for security vulnerability alerts and other distributed information.  The
IBM MSS PGP* public key is available from
   http://www.ers.ibm.com/team-info/pgpkey.html
"Pretty Good Privacy" and "PGP" are trademarks of Philip Zimmermann.

IBM MSS is a Member Team of the Forum of Incident Response and Security
Teams (FIRST), a global organization established to foster cooperation and
response coordination among computer security teams worldwide.

The information in this document is provided as a service to customers of
IBM Managed Security Services.  Neither International Business Machines
Corporation, nor any of its 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 contained herein, or represents that its use would not infringe any
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 IBM or its subsidiaries.  The views and
opinions of authors expressed herein do not necessarily state or reflect
those of IBM or its subsidiaries, and may not be used for advertising or
product endorsement purposes.
===========================================================================

[******  End IBM advisory ******]

_______________________________________________________________________________

CIAC wishes to acknowledge the contributions of IBM Global Services for the 
information contained in this bulletin.
_______________________________________________________________________________


CIAC, the Computer Incident Advisory Center, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.

CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
can be contacted at:
    Voice:    +1 925-422-8193 (7x24)
    FAX:      +1 925-423-8002
    STU-III:  +1 925-423-2604
    E-mail:   ciac@ciac.org

Previous CIAC notices, anti-virus software, and other information are
available from the CIAC Computer Security Archive.

   World Wide Web:      http://www.ciac.org/
   Anonymous FTP:       ftp.ciac.org

PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing
communities receive CIAC bulletins.  If you are not part of these
communities, please contact your agency's response team to report
incidents. Your agency's team will coordinate with CIAC. The Forum of
Incident Response and Security Teams (FIRST) is a world-wide
organization. A list of FIRST member organizations and their
constituencies can be obtained via WWW at http://www.first.org/.

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.

LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC)

L-113: Microsoft Outlook View Control Exposes Unsafe Functionality 
L-114: Hewlett-Packard login Vulnerability 
L-115: Hewlett-Packard dlkm Vulnerability
L-116: Lightweight Directory Access Protocol (LDAP) Vulnerabilities 
L-117: The Code Red Worm 
L-118: Hewlett-Packard ftpd and ftp Vulnerability 
L-119: Hewlett-Packard mkacct Program Vulnerability
L-120: Cisco "Code Red" Worm Impact
L-121: SSH Secure Shell Remote Root Exploit Vulnerability
L-122: FreeBSD tcpdump Remote Buffer Overflow Vulnerability


TUCoPS is optimized to look best in Firefox® on a widescreen monitor (1440x900 or better).
Site design & layout copyright © 1986-2014 AOH