-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN IBM AIX Telnet Denial-of-Service Vulnerability February 11, 1998 19:00 GMT Number I-029 ______________________________________________________________________________ PROBLEM: A vulnerabilty has been identified that causes all tty activity to hang and prevents new telnet sessions. PLATFORM: IBM AIX(r) 4.1.x, 4.2.x, 4.3 DAMAGE: Remote users may cause the system to run out of message blocks and hang. SOLUTION: Apply the fixes listed below. ______________________________________________________________________________ VULNERABILITY This vulnerability has been posted to the Bugtraq mailing list. ASSESSMENT: ______________________________________________________________________________ [ Start IBM Corporation's Advisory ] ======= ============ ====== ====== ======= ============== ======= ======= === === ==== ====== ====== === =========== ======= ======= === =========== === ======= === === === ==== === ===== === ======= ============== ===== === ===== ======= ============ ===== = ===== EMERGENCY RESPONSE SERVICE SECURITY VULNERABILITY ALERT 11 February 1998 13:30 GMT Number: ERS-SVA-E01-1998:003.1 ============================================================================== VULNERABILITY SUMMARY VULNERABILITY: Telnet denial of service attack PLATFORMS: IBM AIX(r) 4.1.x, 4.2.x, 4.3 SOLUTION: Apply the fixes listed below. THREAT: Remote users can cause the system to hang. ============================================================================== DETAILED INFORMATION I. Description A denial of service attack has been posted to the Bugtraq mailing list that causes all tty activity to hang and prevents new telnet sessions from being established. II. Impact Remote users can cause the system to run out of message blocks and hang. III. Solutions A. Official fix At this time, only the AIX 4.1.x APAR is available. AIX 4.2.x and 4.3.0 customers can apply the temporary fix listed below until the official APARs are available. There are no fixes planned for AIX 3.2.5 or earlier. It is recommended that version 3 customers upgrade to version 4. AIX 4.1.x: IX73427 (bos.rte.tty 4.1.5.20) -- available now AIX 4.2.x: IX73580 AIX 4.3.0: IX73214 B. How to alleviate the problem A temporary fix is available for AIX 4.2.x and AIX 4.3.0 via anonymous ftp from: ftp://aix.software.ibm.com/aix/efixes/security/ldterm_fix.tar.Z Filename sum md5 =================================================================== ldterm.42 52419 77 7ec3ff7eb83ded8f50219a838a0a4c0b ldterm.43 37579 77 f066b7d6c3a845c892941a7ab15a6e60 ldterm_fix.sh 10210 3 e3a8bbecda52ff68391657f008b46262 Use the following steps (as root) to install the temporary fix: 1. Use the following command to determine the version of the bos.rte.tty fileset on your machine. # lslpp -l bos.rte.tty If the version is not at the level described below, install the requisite APAR for your release. This will help ensure that the efix binary will run properly. Release bos.rte.tty version requisite APAR ============================================================= AIX 4.2.x less than 4.2.1.9 install IX73755 AIX 4.3.0 less than 4.3.0.3 install IX73397 2. Uncompress and extract the fix. # uncompress < ldterm_fix.tar.Z | tar xf - # cd ldterm_fix 3. Run the ldterm_fix.sh script to install the new tty driver. # ./ldterm_fix.sh 4. Reboot. NOTE: This temporary fix has not been fully regression tested. 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 "aixserv@austin.ibm.com" with the word "FixDist" in the "Subject:" line. V. Acknowledgements Thanks to Kevin Ruderman for bringing this problem to our attention. VI. Contact Information Comments regarding the content of this announcement can be directed to the IBM Support Center or 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@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 1998 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. [ End IBM Corporation's Advisory ] ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of IBM Corporation 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://www.ciac.org/ (or http://ciac.llnl.gov -- they're the same machine) Anonymous FTP: ftp.ciac.org (or ciac.llnl.gov -- they're the same machine) 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. SPI-ANNOUNCE for official news about Security Profile Inspector (SPI) software updates, new features, distribution and availability; 3. 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, 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-bulletin 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. 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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. 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