From ers@VNET.IBM.COM Sat Nov 1 21:54:13 1997 Date: Wed, 29 Oct 1997 14:25:49 -0500 From: ers@VNET.IBM.COM To: BUGTRAQ@NETSPACE.ORG Subject: IBM-ERS Security Vulnerability Alert: The AIX "nslookup" command does not drop privileges correctly ---FOR PUBLIC RELEASE --- -----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 29 October 1997 19:00 GMT Number: ERS-SVA-E01-1997:008.1 =============================================================================== VULNERABILITY SUMMARY VULNERABILITY: The AIX "nslookup" command does not drop privileges correctly PLATFORMS: IBM AIX(r) 4.1, 4.2 SOLUTION: Apply the fixes listed below THREAT: Local users can become root =============================================================================== DETAILED INFORMATION I. Description The nslookup command has a vulnerability that allows local users to become root. II. Solutions A. How to alleviate the problem This problem can be alleviated by removing the set-user-id bit from the "nslookup" program. To do this, execute the following command as "root": chmod 555 /usr/bin/nslookup Removing the set-user-id bit will not result in lost functionality unless /etc/resolv.conf exists and is not world-readable. B. Official fix AIX 4.1 ------- Apply the following fix to your system: APAR - IX71464 To determine if you have this APAR on your system, run the following command: instfix -ik IX71464 Or run the following command: lslpp -h bos.net.tcp.client Your version of bos.net.tcp.client should be 4.1.5.14 or later. AIX 4.2 ------- Apply the following fix to your system: APAR - IX70815 To determine if you have this APAR on your system, run the following command: instfix -ik IX70815 Or run the following command: lslpp -h bos.net.tcp.client Your version of bos.net.tcp.client should be 4.2.1.10 or later. 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". III. Contact Information To request the PGP public key that can be used to encrypt new AIX security vulnerabilities, send email to security-alert@austin.ibm.com with a subject of "get key". If you would like to subscribe to the AIX security newsletter, send a note to aixserv@austin.ibm.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 a registered trademark 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 ers-sales@vnet.ibm.com, 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 iQCVAwUBNFeNrvWDLGpfj4rlAQGamgQAt8DSfVEQUuTSeLhEJUM9Ps/pnWFzlvRi DEGyWD654pXzEfa9+ATAOwqVXU9oCd74S5ly70Pz+hUAUBP2V9aEcM9lKkBl9OJt 0Fymhz+kNSTKPAaqgAZoSUrKEFQLvsRn8IHAZg/fyY1YRM5WbO9TzieOqgKvb//0 dGVTLvxomXw= =XSSm -----END PGP SIGNATURE-----