-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Red Hat Linux "ypbind" Vulnerability October 23, 2000 22:00 GMT Number L-009 _____________________________________________________________________________ PROBLEM: Red Hat has identified a vulnerability in "ypbind". PLATFORM: Red Hat Linux 5.x and 6.x DAMAGE: The logging code in "ypbind" is vulnerable to a printf string format attack that may lead to local root access. SOLUTION: If not needed remove "ypbind" or apply appropriate patches as indicated below. _____________________________________________________________________________ VULNERABILITY Risk is MEDIUM. The vulnerability affects system security and ASSESSMENT: is publicly known. All systems making use of NIS services are encouraged to upgrade. _____________________________________________________________________________ [****** Start Red Hat Security Advisory ******] - --------------------------------------------------------------------- Red Hat, Inc. Security Advisory Synopsis: ypbind for Red Hat Linux 5.x, 6.x has a local root exploit Advisory ID: RHSA-2000:086-05 Issue date: 2000-10-16 Updated on: 2000-10-23 Product: Red Hat Linux Keywords: ypbind string format buffer overflow syslog Cross references: N/A - --------------------------------------------------------------------- 1. Topic: ypbind as shipped in Red Hat Linux 5.x and 6.x is vulnerable to a local root exploit. All systems making use of NIS services are encouraged to upgrade. 2. Relevant releases/architectures: Red Hat Linux 5.0 - i386, alpha, sparc Red Hat Linux 5.1 - i386, alpha, sparc Red Hat Linux 5.2 - i386, alpha, sparc Red Hat Linux 6.0 - i386, alpha, sparc Red Hat Linux 6.1 - i386, alpha, sparc Red Hat Linux 6.2 - i386, alpha, sparc Red Hat Linux 6.2EE - i386, alpha, sparc 3. Problem description: Systems using Network Information Service, or NIS, use a daemon called ypbind to request information from a NIS server. This information is then used by the local machine. The logging code in ypbind is vulnerable to a printf string format attack which an attacker could exploit by passing ypbind a carefully crafted request. This attack can successfully lead to local root access. This problem has been corrected with these new packages. 4. Solution: If you do not use NIS, you should remove ypbind: rpm -e ypbind Otherwise, for each RPM for your particular architecture, run: rpm -Fvh [filename] where filename is the name of the RPM. You should then make sure that the new ypbind is running by issuing: /etc/rc.d/init.d/ypbind restart 5. Bug IDs fixed (http://bugzilla.redhat.com/bugzilla for more info): N/A 6. RPMs required: Red Hat Linux 5.x: alpha: ftp://updates.redhat.com/5.2/alpha/ypbind-3.3-10.alpha.rpm sparc: ftp://updates.redhat.com/5.2/sparc/ypbind-3.3-10.sparc.rpm i386: ftp://updates.redhat.com/5.2/i386/ypbind-3.3-10.i386.rpm sources: ftp://updates.redhat.com/5.2/SRPMS/ypbind-3.3-10.src.rpm Red Hat Linux 6.x: alpha: ftp://updates.redhat.com/6.2/alpha/ypbind-1.7-0.6.x.alpha.rpm sparc: ftp://updates.redhat.com/6.2/sparc/ypbind-1.7-0.6.x.sparc.rpm i386: ftp://updates.redhat.com/6.2/i386/ypbind-1.7-0.6.x.i386.rpm sources: ftp://updates.redhat.com/6.2/SRPMS/ypbind-1.7-0.6.x.src.rpm 7. Verification: MD5 sum Package Name - -------------------------------------------------------------------------- 507ff0e63468e829b2c917789ba2fedd 5.2/SRPMS/ypbind-3.3-10.src.rpm 127274f9828d27f895e8d8eee8d38db6 5.2/alpha/ypbind-3.3-10.alpha.rpm 7bbf68a42a3c996c6f69b5ffaf2911f7 5.2/i386/ypbind-3.3-10.i386.rpm 3d0cd8b8700182b9b815525e1f99c82d 5.2/sparc/ypbind-3.3-10.sparc.rpm d8caa439a1b6c7b26f843bacd01c65f8 6.2/SRPMS/ypbind-1.7-0.6.x.src.rpm 3a426e3060d31aa37b2a41d973ac3f63 6.2/alpha/ypbind-1.7-0.6.x.alpha.rpm 411017238af9a0a8891bd3078547336c 6.2/i386/ypbind-1.7-0.6.x.i386.rpm 3beff51d6a0292fd9d50fe24d07097ac 6.2/sparc/ypbind-1.7-0.6.x.sparc.rpm These packages are GPG signed by Red Hat, Inc. for security. Our key is available at: http://www.redhat.com/corp/contact.html You can verify each package with the following command: rpm --checksig If you only wish to verify that each package has not been corrupted or tampered with, examine only the md5sum with the following command: rpm --checksig --nogpg 8. References: N/A Copyright(c) 2000 Red Hat, Inc. [****** End Red Hat Security Advisory ******] _____________________________________________________________________________ CIAC wishes to acknowledge the contributions of Red Hat, Inc. 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: +1 925-422-8193 FAX: +1 925-423-8002 STU-III: +1 925-423-2604 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), use one of the following methods to contact CIAC: 1. Call the CIAC voice number 925-422-8193 and leave a message, or 2. Call 888-449-8369 to send a Sky Page to the CIAC duty person or 3. Send e-mail to 4498369@skytel.com, or 4. Call 800-201-9288 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 (925) 423-4753 (28.8K baud) +1 (925) 423-3331 (28.8K baud) 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. 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