Original issue date: April 24, 1997<BR>
Last revised: September 26, 1997<BR>
Updated copyright statement
<P>A complete revision history is at the end of this file.
<P>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.
<P>Exploitation information is publicly available.
<P>The CERT/CC team recommends installing patches when they become
available.
<P>We will update this advisory as we receive additional
information. Please check advisory files regularly for updates that
relate to your site.
<P><HR>
<H2>I. Description</H2>
<P>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.
<P>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.
<P>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.
<P>Exploit information involving this vulnerability has been made
publicly available.
<BR>
<H2>II. Impact</H2>
<P>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.
<H2>III. Solution</H2>
<P>Install a patch for this problem when one becomes
available. Currently, there is no workaround to use in the meantime.
<P>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.
<P>Berkeley Software Design, Inc. (BSDI)
<BR>Cray Research - A Silicon Graphics Company
<BR>Data General Corporation
<BR>Digital Equipment Corporation
<BR>Hewlett-Packard Company
<BR>IBM Corporation
<BR>Linux Systems
<BR>NEC Corporation
<BR>NeXT/Apple
<BR>The Santa Cruz Operation (SCO)
<BR>Solbourne
<BR>Sun Microsystems, Inc.
<P><HR>
<H2>Appendix A - Vendor Information</H2>
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.
<BR>
<H3>Berkeley Software Design, Inc. (BSDI)</H3>
No versions of BSD/OS are vulnerable to this problem.
<BR>
<H3>Cray Research - A Silicon Graphics Company</H3>
This problem has been resolved with code that is available in released
software packages as described in the FIX AVAILABILITY section below.
<H4>FIX AVAILABILITY</H4>
For each affected product level, the following table identifies the release
that contains the fix:
<BR>
<TABLE BORDER=0 WIDTH="100%" NOSAVE >
<TR>
<TD>Affected Product</TD>
<TD>Release Levels Containing Fix</TD>
</TR>
<TR>
<TD>UNICOS</TD>
<TD>UNICOS 9.0.2.5</TD>
</TR>
<TR>
<TD></TD>
<TD>UNICOS 9.2.0.4</TD>
</TR>
<TR>
<TD>UNICOS/mk</TD>
<TD>UNICOS/mk 1.5.1</TD>
</TR>
<TR>
<TD>UNICOS MAX</TD>
<TD>UNICOS MAX 1.3.0.5</TD>
</TR>
</TABLE>
<H4>RELATED INFORMATION</H4>
SPR 704175 POSSIBLE SECURITY PROBLEM IN SETLOCALE
<BR>
<H3>Data General Corporation</H3>
We're investigating.
<BR>
<BR>
<H3>Digital Equipment Corporation</H3>
<H4>SOURCE:</H4>
Digital Equipment Corporation
<BR>Software Security Response Team
<BR>Copyright (c) Digital Equipment Corporation 1997. All rights reserved.
<P>This reported problem is not present for Digital's ULTRIX or Digital
UNIX Operating Systems Software.
<BR>
<H3>Hewlett-Packard Company</H3>
HP has completed their testing, HP-UX is not vulnerable.
<H3>IBM Corporation</H3>
All AIX releases are vulnerable to a variation of this advisory.
<H4>AIX 3.2.5</H4>
Apply the following fix to your system:
<P>PTFs - U447656 U447671 U447676 U447682 U447705 U447723 (APAR IX67405)
<P>To determine if you have these PTFs on your system, run the following
command:
<P>lslpp -lB U447656 U447671 U447676 U447682 U447705 U447723
<H4>AIX 4.1</H4>
Apply the following fix to your system:
<P>APAR - IX67407
<P>To determine if you have this APAR on your system, run the following
command:
<P>instfix -ik IX67407
<P>Or run the following command:
<P>lslpp -h bos.rte.libc
<P>Your version of bos.rte.libc should be 4.1.5.7 or later.
<H4>AIX 4.2</H4>
Apply the following fixes to your system:
<P>APAR - IX67377 IX65693
<P>To determine if you have these APARs on your system, run the following
command:
<P>instfix -ik IX67377 IX65693
<P>Or run the following command:
<P>lslpp -h bos.rte.libc
<P>Your version of bos.rte.libc should be 4.2.0.11 or later.
<P>(APAR IX65693 fixes a problem with the mkgroup command after IX67377
is applied.)
<H4>To Order</H4>
APARs may be ordered using Electronic Fix Distribution (via FixDist) or
from the IBM Support Center. For more information on FixDist, reference
URL:
<P><A HREF="http://service.software.ibm.com/aixsupport/">http://service.software.ibm.com/aixsupport/</A>
<P>or send e-mail to <A HREF="mailto:aixserv@austin.ibm.com">aixserv@austin.ibm.com</A>
with a subject of "FixDist".
<BR>
<P>IBM and AIX are registered trademarks of International Business Machines
Corporation.
<BR>
<H3>Linux Systems</H3>
Linux systems running older C libraries are vulnerable. To check which
C library is being used type
<P>linux% ldd /bin/ls
<P>libc.so.5 => /lib/libc.so.5.3.12
<P>This indicates the machine is using libc 5.3.12.
<P>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.
<P>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:
<P>linux# rpm -q libc
<P>libc-5.3.12-17
<P>Indicates you have version 17 of the package. This is the safe one.
<P>Red Hat 4.0 users who have not already upgraded their libc can obtain
this package at
<P><A HREF="ftp://ftp.redhat.com/pub/redhat/old-releases/redhat-4.0/updates/">ftp://ftp.redhat.com/pub/redhat/old-releases/redhat-4.0/updates/</A>.
<BR>
<H3>NEC Corporation</H3>
NEC platforms are not affected by this vulnerability.
<BR>
<H3>NeXT/Apple</H3>
No versions of NeXTstep of OpenStep/Mach are vulnerable to this problem.
<BR>
<H3>The Santa Cruz Operation (SCO)</H3>
We are investigating this problem and will provide updated information
for this advisory when it becomes available.
<BR>
<H3>Solbourne</H3>
Solbourne is not vulnerable.
<BR>
<H3>Sun Microsystems, Inc.</H3>
Not vulnerable.
<P><HR>
<P>The CERT Coordination Center staff thanks Wolfgang Ley of DFN-CERT
for his input to this advisory and Bruce Ide for drawing our attention
to the problem.
<P><HR>
<H2>UPDATES</H2>
There appear to be several slightly different descriptions for the NLS
acronym. They are included here for convenience:
<BR>
<P>National Language Service
<BR>National Language Support
<BR>Native Language System
<BR>Natural Language Service
<BR>Natural Language Support
<P><HR>
<P><HR>
<!--#include virtual="/include/footer_nocopyright.html" -->
<P>Copyright 1997 Carnegie Mellon University.</P>
<HR>
Revision History
<PRE>
Sep. 26, 1997 Updated copyright statement
June 3, 1997 Updates section - added other phrases for the the NLS acronym
Appendix A - updated Cray Research entry.
May 1, 1997 Section III and Appendix. Updated vendor information
for Hewlett-Packard Company.
Acknowledgments - added a name upon receiving
permission to do so.
</PRE>
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