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-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-97.130 -- IBM security vulnerability alert Buffer overflow in the "xdat" command 22 October 1997 =========================================================================== IBM-ERS has released the following advisory concerning a buffer overflow vulnerability in the xdat command under IBM AIX(r) 4.1, 4.2. This vulnerability may allow local users to gain root access. The following security bulletin is provided as a service to AUSCERT's members. As AUSCERT did not write this document, AUSCERT has had no control over its content. As such, the decision to use any or all of this information is the responsibility of each user or organisation, and should be done so in accordance with site policies and procedures. Contact information for IBM-ERS is included in the Security Bulletin below. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/information/advisories.html If you believe that your system has been compromised, contact AUSCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: email@example.com Facsimile: (07) 3365 4477 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AUSCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for emergencies. - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- - - --ERS-ALERT--ERS-ALERT--ERS-ALERT--ERS-ALERT--ERS-ALERT--ERS-ALERT--ERS-ALERT-- - - ---EXTERNAL RELEASE---EXTERNAL RELEASE---EXTERNAL RELEASE---EXTERNAL RELEASE--- ======= ============ ====== ====== ======= ============== ======= ======= === === ==== ====== ====== === =========== ======= ======= === =========== === ======= === === === ==== === ===== === ======= ============== ===== === ===== ======= ============ ===== = ===== EMERGENCY RESPONSE SERVICE SECURITY VULNERABILITY ALERT 21 October 1997 16:00 GMT Number: ERS-SVA-E01-1997:004.1 =============================================================================== VULNERABILITY SUMMARY VULNERABILITY: Buffer overflow in the IBM AIX "xdat" command PLATFORMS: IBM AIX(r) 4.1, 4.2 SOLUTION: Remove the setuid bit or apply one of the fixes below THREAT: Local users may become root =============================================================================== DETAILED INFORMATION I. Description The "xdat" command shipped with AIX version 4 does not check the length of the "TZ" environment variable. This command was not shipped with AIX 3.2. II. Impact Local users may become root. III. Solutions A. How to alleviate the problem This problem can be alleviated by removing the set-user-id bit from the "xdat" program. To do this, execute the following command as "root": chmod 555 /usr/lpp/X11/bin/xdat B. Official fix IBM is currently working on the following APARs but they are not yet available. AIX 4.1: IX72020 AIX 4.2: IX72021 C. Temporary fixes A temporary fix is available via anonymous ftp from: ftp://testcase.software.ibm.com/aix/fromibm/security.xdat.tar.Z Filename sum md5 ================================================================= xdat 44047 74 33bcec8bbc7d8eb2e4e2ae760d2b986e Use the following steps (as root) to install the temporary fix: 1. Uncompress and extract the fix: # uncompress < security.xdat.tar.Z | tar xf - 2. Use the "xdat_patch.sh" script or the following manual commands: # pgp xdat/xdat.pgp xdat/xdat # cp /usr/lpp/X11/bin/xdat /usr/lpp/X11/bin/xdat.orig # chmod -s /usr/lpp/X11/bin/xdat.orig # cp xdat/xdat /usr/lpp/X11/bin/xdat # chmod 4555 /usr/lpp/X11/bin/xdat This fix has not been fully regression tested but does prevent the TZ environment variable exploit. If the new executable fails to load due to missing symbols, the following APARs may help to resolve the prerequisites: AIX 4.1: IX69580 AIX 4.2: IX69180 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://service.software.ibm.com/aixsupport/ or send electronic mail to "firstname.lastname@example.org" with the word "FixDist" in the "Subject:" line. V. Acknowledgements Thanks to Bryan Self <email@example.com> for bringing this problem to our attention. VI. AIX Security Contact Information To request the PGP public key that can be used to encrypt new AIX security vulnerabilities, send email to firstname.lastname@example.org with a subject of "get key". If you would like to subscribe to the AIX security newsletter, send a note to email@example.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 registered trademarks of International Business Machines Corporation. All other trademarks are property of their respective holders. =============================================================================== IBM's Internet Emergency Response Service (IBM-ERS) 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-ERS'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 Recovery Services organization, the IBM Internet Emergency Response Service is a component of IBM's SecureWay(tm) line of security products and services. From hardware to software to consulting, SecureWay solutions can give you the assurance and expertise you need to protect your valuable business resources. To find out more about the IBM Internet Emergency Response Service, send an electronic mail message to firstname.lastname@example.org, or call 1-800-742-2493 (Prompt 4). IBM-ERS 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-ERS uses Pretty Good Privacy* (PGP*) as the digital signature mechanism for security vulnerability alerts and other distributed information. The IBM-ERS 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-ERS 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. Copyright 1997 International Business Machines Corporation. The information in this document is provided as a service to customers of the IBM Emergency Response Service. Neither International Business Machines Corporation, Integrated Systems Solutions Corporation, 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 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. The material in this security alert may be reproduced and distributed, without permission, in whole or in part, by other security incident response teams (both commercial and non-commercial), provided the above copyright is kept intact and due credit is given to IBM-ERS. This security alert may be reproduced and distributed, without permission, in its entirety only, by any person provided such reproduction and/or distribution is performed for non-commercial purposes and with the intent of increasing the awareness of the Internet community. - - ---EXTERNAL RELEASE---EXTERNAL RELEASE---EXTERNAL RELEASE---EXTERNAL RELEASE--- - - --ERS-ALERT--ERS-ALERT--ERS-ALERT--ERS-ALERT--ERS-ALERT--ERS-ALERT--ERS-ALERT-- - -----BEGIN PGP SIGNATURE----- Version: 2.7.1 iQCVAwUBNEzfVvWDLGpfj4rlAQEnHwP/UiN0WN/r1D0VLooXF1jTZvmnEXtUaoO4 xwmjJFbo+TNTqAjUpCMz7m7aaDqKTwdDFY4QAVA2GShf+712emkSErEoTNRUJI3j GBc1wi3fzHqExcpWIubSvjR8Po7vaV7nnC34d3mtXBErK4mq39Y1IHQtFGIuYtWf UtgCKtflRD8= =GZxD - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBNE3MKCh9+71yA2DNAQFtigQAka8xqnCUQ1RWFxwhkR2fq3uTZ4vy4Bz9 xKFK5NfJmsPxQaK4mk6yCmvAupL/S1A2UEDBKuBPkQIYIJ1AY5X/1oTNIxNm8DOT bwVaJcXue85fW5x09IOyDG8uieplViRs1acCzyhzYE0meXAhizxfzYvxcjC+30hc +hBfvC5dzzU= =Tre3 -----END PGP SIGNATURE-----