-----BEGIN PGP SIGNED MESSAGE----- ============================================================================= CERT* Advisory CA-97.10 Original issue date: April 24, 1997 Last revised: June 3, 1997 Updates section - added other phrases for the the NLS acronym. Appendix A - updated Cray Research entry. Topic: Vulnerability in Natural Language Service - ----------------------------------------------------------------------------- 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. - ----------------------------------------------------------------------------- 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 ========================================== This problem has been resolved with code that is available in released software packages as described in the FIX AVAILABILITY section below. FIX AVAILABILITY ---------------- For each affected product level, the following table identifies the release that contains the fix: Release Levels Affected Product Containing Fix ================ ============== UNICOS UNICOS 9.0.2.5 UNICOS 9.2.0.4 UNICOS/mk UNICOS/mk 1.5.1 UNICOS MAX UNICOS MAX 1.3.0.5 RELATED INFORMATION ------------------- SPR 704175 POSSIBLE SECURITY PROBLEM IN SETLOCALE 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 ======================= HP has completed their testing, HP-UX is not vulnerable. 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. - ----------------------------------------------------------------------------- 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. - ----------------------------------------------------------------------------- If you believe that your system has been compromised, contact the CERT Coordination Center or your representative in the Forum of Incident Response and Security Teams (see http://www.first.org/team-info). CERT/CC Contact Information - ---------------------------- Email cert@cert.org Phone +1 412-268-7090 (24-hour hotline) CERT personnel answer 8:30-5:00 p.m. EST(GMT-5) / EDT(GMT-4) and are on call for emergencies during other hours. Fax +1 412-268-6989 Postal address CERT Coordination Center Software Engineering Institute Carnegie Mellon University Pittsburgh PA 15213-3890 USA Using encryption We strongly urge you to encrypt sensitive information sent by email. We can support a shared DES key or PGP. Contact the CERT/CC for more information. Location of CERT PGP key ftp://info.cert.org/pub/CERT_PGP.key Getting security information CERT publications and other security information are available from http://www.cert.org/ ftp://info.cert.org/pub/ CERT advisories and bulletins are also posted on the USENET newsgroup comp.security.announce To be added to our mailing list for advisories and bulletins, send email to cert-advisory-request@cert.org In the subject line, type SUBSCRIBE your-email-address - --------------------------------------------------------------------------- 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. - --------------------------------------------------------------------------- This file: ftp://info.cert.org/pub/cert_advisories/CA-97.10.nls http://www.cert.org click on "CERT Advisories" ============================================================================= UPDATES There appear to be several slightly different descriptions for the NLS acronym. They are included here for convenience: National Language Service National Language Support Native Language System Natural Language Service Natural Language Support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Revision history 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 Appendex. Updated vendor information for Hewlett-Packard Company. Acknowledgments - added a name upon receiving permission to do so. -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBM5Vn/XVP+x0t4w7BAQGvqgP/USJkyW64Ad+NOccCycyLU0r6orGkcXxI zef4y2umkXzzdns3RbPKloEmMb6Pw/KsDiIFeopvVRRoyQnBLMy1it0qs8Y8ssgS LP227eVhMFHbPSxVoLMo10ftlD/Q0HgsVllGnujFfR4bFJESanWtYjJuamZzY21R uyAxyeIvqTU= =yYLW -----END PGP SIGNATURE-----