Conference minotr::security_advisory

138.0. "Information Only: CERT CA:97-10, NLS Vulnerability" by MINOTR::NOBLE (Your Data, Your Job...Protect Both) Thu Apr 24 1997 20:03

                                      
    The Digital Corporate Information Security Group has received the
    following external security notice.  It should be noted that Digital
    UNIX is not impacted by this reported security vulnerability.
        
    This third party notice is being provided as information only.  No
    recommendation is made with regards the solution(s) identified.
    
    Should you happen to be using a third party software impacted by
    this notice, please use due discretion before implementing any or all
    of the solution(s) identified.
    
    If you are an internal user of any software impacted in this notice,
    and have any questions regarding this notice, then please contact your
    IT Cluster Security Manager.  An up-to-date list can be found at URL
    http://www-is-security.mso.dec.com/is-sec/gen-info/contact-menu.html
      
                                  -=<>=-
    

    
    
    
=============================================================================
CERT* Advisory CA-97.10
Original issue date: April 24, 1997
Last revised: --
              
Topic: Vulnerability in Natural Language Service
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The CERT Coordination Center has received reports of a buffer overflow
condition that affects some libraries using the Natural Language Service (NLS)
on UNIX systems. By exploiting this vulnerability, any local user can execute
arbitrary programs as a privileged user. There is a possibility (with some old
libraries) that the vulnerability can be exploited by a remote user.

Exploitation information is publicly available.

The CERT/CC team recommends installing patches when they become available.

We will update this advisory as we receive additional information.
Please check advisory files regularly for updates that relate to your site.

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I.   Description

     A buffer overflow condition affects libraries using the Natural Language
     Service (NLS). The NLS is the component of UNIX systems that provides
     facilities for customizing the natural language formatting for the
     system. Examples of the types of characteristics that can be set are
     language, monetary symbols and delimiters, numeric delimiters, and time
     formats.

     Some libraries that use a particular environment variable associated with
     the NLS contain a vulnerability in which a buffer overflow condition can
     be triggered. The particular environment variable involved is NLSPATH on
     some systems and PATH_LOCALE on others.

     It is possible to exploit this vulnerability to attain unauthorized
     access by supplying carefully crafted arguments to programs that are
     owned by a privileged user-id and that have setuid or setgid bits set.

     Exploit information involving this vulnerability has been made
     publicly available.


II.  Impact

     Local users (users with access to an account on the system) are able to
     execute arbitrary programs as a privileged user without authorization.
     There is a possibility (with some old libraries) that the vulnerability
     can be exploited by a remote user. 

III. Solution

     Install a patch for this problem when one becomes available. 
     Currently, there is no workaround to use in the meantime.

     Below is a list of vendors who have provided information about this
     problem. Details are in Appendix A of this advisory; we will update the
     appendix as we receive more information. If your vendor's name is not on
     this list, the CERT/CC did not hear from that vendor. Please contact your
     vendor directly.

        Berkeley Software Design, Inc. (BSDI)
        Cray Research - A Silicon Graphics Company
        Data General Corporation
        Digital Equipment Corporation
        Hewlett-Packard Company
        IBM Corporation
        Linux Systems
        NEC Corporation
        NeXT/Apple        
        The Santa Cruz Operation (SCO)
        Solbourne
        Sun Microsystems, Inc.

...........................................................................

Appendix A - Vendor Information

Below is a list of the vendors who have provided information for this
advisory. We will update this appendix as we receive additional information.
If you do not see your vendor's name, the CERT/CC did not hear from that
vendor. Please contact the vendor directly.


Berkeley Software Design, Inc. (BSDI)
=====================================
  No versions of BSD/OS are vulnerable to this problem.


Cray Research - A Silicon Graphics Company
==========================================
  We're investigating.


Data General Corporation
========================
  We're investigating.


Digital Equipment Corporation
=============================
SOURCE:  
 
   Digital Equipment Corporation                         
   Software Security Response Team
   Copyright (c) Digital Equipment Corporation 1997. All rights reserved.
 
    This reported problem is not present for Digital's ULTRIX or
    Digital UNIX Operating Systems Software.
   
 
Hewlett-Packard Company
=======================
  Investigation in process, results -to date- indicate HP not
  vulnerable. This advisory will be updated when investigation is complete.
 

IBM Corporation
===============
  All AIX releases are vulnerable to a variation of this advisory.
 
  AIX 3.2.5
  ---------
 
    Apply the following fix to your system:
 
    PTFs - U447656 U447671 U447676 U447682 U447705 U447723  (APAR IX67405)
 
    To determine if you have these PTFs on your system, run the following
    command:
 
       lslpp -lB U447656 U447671 U447676 U447682 U447705 U447723
 
  AIX 4.1
  -------
 
    Apply the following fix to your system:
 
        APAR - IX67407
 
    To determine if you have this APAR on your system, run the following
    command:
 
       instfix -ik IX67407
 
    Or run the following command:
    
       lslpp -h bos.rte.libc
 
    Your version of bos.rte.libc should be 4.1.5.7 or later.
 
  AIX 4.2
  -------
    Apply the following fixes to your system:
 
        APAR - IX67377 IX65693
 
    To determine if you have these APARs on your system, run the following
    command:
 
       instfix -ik IX67377 IX65693
 
    Or run the following command:
    
       lslpp -h bos.rte.libc
 
    Your version of bos.rte.libc should be 4.2.0.11 or later.
 
    (APAR IX65693 fixes a problem with the mkgroup command after IX67377
    is applied.)

  To Order
  --------
    APARs may be ordered using Electronic Fix Distribution (via FixDist)
    or from the IBM Support Center.  For more information on FixDist,
    reference URL:
 
       http://service.software.ibm.com/aixsupport/
 
    or send e-mail to aixserv@austin.ibm.com with a subject of "FixDist".
 
 
  IBM and AIX are registered trademarks of International Business Machines
  Corporation.


Linux Systems
=============
  Linux systems running older C libraries are vulnerable. To check which C
  library is being used type

  linux% ldd /bin/ls
          libc.so.5 => /lib/libc.so.5.3.12

  This indicates the machine is using libc 5.3.12.

  C libraries older than 5.3.12 (that is libc5.2.18, libc5.0.9 etc) are
  vulnerable to this bug and you should upgrade the C library. The release
  versions of libc 5.4.x are immune to this attack.

  If you have libc5.3.12 it is insecure unless it is the modified
  libc5.3.12 shipped with Red Hat 4.1, or as an upgrade on Red Hat 4.0. You
  can check this with the package manager:

  linux# rpm -q libc
  libc-5.3.12-17

  Indicates you have version 17 of the package. This is the safe one.

  Red Hat 4.0 users who have not already upgraded their libc can obtain
  this package at

     ftp://ftp.redhat.com/pub/redhat/old-releases/redhat-4.0/updates/.


NEC Corporation
===============
  NEC platforms are not affected by this vulnerability.
 

NeXT/Apple
==========
  No versions of NeXTstep of OpenStep/Mach are vulnerable to this problem.


The Santa Cruz Operation (SCO)
=============================
  We are investigating this problem and will provide updated information
  for this advisory when it becomes available.


Solbourne
=========
  Solbourne is not vulnerable.


Sun Microsystems, Inc.
======================
  Not vulnerable.

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The CERT Coordination Center staff thanks Wolfgang Ley of DFN-CERT for his
input to this advisory.
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Copyright 1997 Carnegie Mellon University
This material may be reproduced and distributed without permission provided
it is used for noncommercial purposes and the copyright statement is
included.

* Registered U.S. Patent and Trademark Office.
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