-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN NLS Buffer Overflow Vulnerability April 24, 1997 21:00 GMT Number H-49 ______________________________________________________________________________ PROBLEM: A vulnerability exists in libraries using Natural Language Service (NLS). PLATFORM: AIX 4.2 and earlier Linux libc 5.3.12 and earlier DAMAGE: Local and possibility remote users may gain root privileges. SOLUTION: Take the steps outlined in Section III as soon as possible. ______________________________________________________________________________ VULNERABILITY Exploit details involving this vulnerability have been made ASSESSMENT: publicly available. ______________________________________________________________________________ [****** Start CERT Advisory ******] ============================================================================= CERT* Advisory CA-97.10 Original issue date: April 24, 1997 Last revised: -- 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 ========================================== 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. [****** End CERT Advisory ******] ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of CERT and Wolfgang Ley of DFN- CERT for the information contained in this bulletin. ______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, 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: +1 510-422-8193 FAX: +1 510-423-8002 STU-III: +1 510-423-2604 E-mail: ciac@llnl.gov For emergencies and off-hour assistance, DOE, DOE contractor sites, and the NIH may contact CIAC 24-hours a day. During off hours (5PM - 8AM PST), call the CIAC voice number 510-422-8193 and leave a message, or call 800-759-7243 (800-SKY-PAGE) to send a Sky Page. CIAC has two Sky Page PIN numbers, the primary PIN number, 8550070, is for the CIAC duty person, and the secondary PIN number, 8550074 is for the CIAC Project Leader. Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://ciac.llnl.gov/ Anonymous FTP: ciac.llnl.gov (128.115.19.53) Modem access: +1 (510) 423-4753 (28.8K baud) +1 (510) 423-3331 (28.8K baud) CIAC has several self-subscribing mailing lists for electronic publications: 1. CIAC-BULLETIN for Advisories, highest priority - time critical information and Bulletins, important computer security information; 2. CIAC-NOTES for Notes, a collection of computer security articles; 3. SPI-ANNOUNCE for official news about Security Profile Inspector (SPI) software updates, new features, distribution and availability; 4. SPI-NOTES, for discussion of problems and solutions regarding the use of SPI products. Our mailing lists are managed by a public domain software package called Majordomo, which ignores E-mail header subject lines. To subscribe (add yourself) to one of our mailing lists, send the following request as the E-mail message body, substituting ciac-bulletin, ciac-notes, spi-announce OR spi-notes for list-name: E-mail to ciac-listproc@llnl.gov or majordomo@tholia.llnl.gov: subscribe list-name e.g., subscribe ciac-notes You will receive an acknowledgment email immediately with a confirmation that you will need to mail back to the addresses above, as per the instructions in the email. This is a partial protection to make sure you are really the one who asked to be signed up for the list in question. If you include the word 'help' in the body of an email to the above address, it will also send back an information file on how to subscribe/unsubscribe, get past issues of CIAC bulletins via email, etc. 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) H-38A: Internet Explorer 3.x Vulnerabilities H-39: SGI IRIX fsdump Vulnerability H-40: DIGITAL Security Vulnerabilities (DoP, delta-time) H-41: Solaris 2.x eject Buffer Overrun Vulnerability H-42: HP MPE/iX with ICMP Echo Request (ping) Vulnerability H-44: Solaris 2.x fdformat Buffer Overflow Vulnerability H-45: Windows NT SAM permission Vulnerability H-46: Vulnerability in IMAP and POP H-47A: AOL4FREE.COM Trojan Horse Program Destroys Hard Drives H-48: Internet Information Server Vulnerability -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBM2YTvLnzJzdsy3QZAQHnSwP/QORIMX2R5lkYmkEHIXIl+FJ4dW0prhT3 Kb0A0aNyuzi6i1QkbvlLCSkAvK8+gXjNYzYAKrBAvSHVjHVlmahBW9bfQQ8pFg9i Zn1mdPCF/hDXKnCd4QrARAiAhQmrE1uyu8D1P6sBj5/ZWhYHys9W5S9Irkq/lAeI K++7BeA8rco= =Bwbu -----END PGP SIGNATURE-----