Published:
26 July 1999
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-1999.103 -- IBM-ERS Security Vulnerability Alert #1999:002.1 IBM AIX: Non-root users can cause the system to crash 27 July 1999 =========================================================================== The IBM Emergency Response Service has released the following alert concerning a denial of service vulnerability in the ptrace() system call of AIX versions 4.2.x and 4.3.x. This vulnerability may allow non-root users to crash the system. - ---------------------------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 26 July 1999 15:00 GMT Number: ERS-SVA-E01-1999:002.1 =============================================================================== VULNERABILITY SUMMARY VULNERABILITY: Non-root users can cause the system to crash PLATFORMS: IBM AIX(r) 4.2.x, 4.3.x SOLUTION: Apply the fixes listed below. =============================================================================== DETAILED INFORMATION I. Description A denial of service vulnerability has been discovered in the ptrace() system call of AIX versions 4.2.x and 4.3.x allowing non-root users to crash the system. This vulnerability has been posted to the bugtraq mailing list. II. Solutions A. Official fix IBM is working on the following fixes which will be available soon. AIX 3.2.x: upgrade to version 4 AIX 4.1.x: not vulnerable AIX 4.2.x: IY02381 AIX 4.3.x: IY02397 B. How to alleviate the problem A temporary fix is available via anonymous ftp from: ftp://aix.software.ibm.com/aix/efixes/security/adb_hang.tar.Z Filename sum md5 ====================================================================== unix_mp.42.adb_hang_fix 00772 2693 960214a1945f2c70311283adc0b231a3 unix_mp.43.adb_hang_fix 15044 3302 584d1c5ea0223110e2d8eba84388f526 This temporary fix has not been fully regression tested. The fix consists of a multiprocessor kernel which can be used on either a uniprocessor or multiprocessor machine. There may be a slight performance penalty when using a multiprocessor kernel on a uniprocessor machine. Use the following steps (as root) to install the temporary fix: 1. Determine the version of the kernel fileset on your machine. # lslpp -l <fileset> If the version of the kernel fileset for your machine is not at the level described below, install the requisite APAR listed. This will help ensure that the temporary kernel fix will run properly. Release Fileset Version requisite APAR =============================================================== AIX 4.2.x bos.mp or bos.up 4.2.1.23 IY00689 AIX 4.3.x bos.mp or bos.up 4.3.2.8 IY00727 2. Uncompress and extract the fix. # uncompress < adb_hang.tar.Z | tar xf - # cd adb_hang 3. Review and run the adb_hang.sh script to install the new kernel. # view ./adb_hang.sh # ./adb_hang.sh 4. Reboot. III. 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://aix.software.ibm.com/aix.us/swfixes/ or send email to "aixserv@austin.ibm.com" with the word "FixDist" in the "Subject:" line. To facilitate ease of ordering all security related APARs for each AIX release, security fixes are periodically bundled into a cumulative APAR. For more information on these cumulative APARs including last update and list of individual fixes, send email to "aixserv@austin.ibm.com" with the word "subscribe Security_APARs" in the "Subject:" line. IV. Contact Information Comments regarding the content of this announcement can be directed to: security-alert@austin.ibm.com 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@ers.ibm.com, or call 1-800-599-9950. 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 1999 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, nor any of its employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, complete- ness, 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 iQCVAwUBN5x72vWDLGpfj4rlAQGaTgQA4EtxpIcdMDmpoChMyHKombitQfJxfIt1 9xPkvey8yCQpjJPtfoyF+hfK2Rs0a42pA++8RXvV+8suq8JMyOFoyFIqB+E72hFd ZCgKyxGpMhWnE4gmHIFaZjWsasZjk7XDGkaXOpwnYzv5jrZEapLrOSFROSPOBsXX dh9DkBQBnNU= =WqO0 - -----END PGP SIGNATURE----- - ---------------------------END INCLUDED TEXT-------------------- This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. 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. NOTE: This is only the original release of the security bulletin. It will not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the original authors to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. 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: auscert@auscert.org.au Facsimile: (07) 3365 7031 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 PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBN+dvrCh9+71yA2DNAQFIFQP/Ryr3im6Wt3hQi4nYeUowlvNmRACQqRLw X4afioGfrs4NpO67LTVKvM5y9rNurcGcMNgtGP3qoaPYmFO5q0KJa0FiUGmES8hf 0cI3giyf7gX5AT/dUxJ+9CDEg4LACPrtHRiH+meGsOebpO98UzqY0aIFO/Uwalln +YRajGnGBdM= =SqhI -----END PGP SIGNATURE-----