__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Center ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Red Hat Linux PAM Vulnerability October 23, 2001 19:00 GMT Number M-009 ______________________________________________________________________________ PROBLEM: A software vulnerability exists in the PAM authentication process. PAM authentication may not be properly enforced in non-default setups. PLATFORM: Red Hat Linux 7.1: Alpha i386 ia64 Red Hat Linux 7.2: i386 DAMAGE: System users may receive the authentication credentials of other users. SOLUTION: Red Hat recommends that all users update to the latest package. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. This vulnerability has been publicly ASSESSMENT: announced. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/m007.shtml ORIGINAL BULLETIN: http://www.redhat.com/support/errata/RHSA-2001-132.html PATCHES: Red Hat Linux 7.1: SRPMS: ftp://updates.redhat.com/7.1/en/os/SRPMS/util-linux-2.11f-11.7.1.src.rpm alpha: ftp://updates.redhat.com/7.1/en/os/alpha/util-linux-2.11f-11.7.1.alpha.rpm i386: ftp://updates.redhat.com/7.1/en/os/i386/util-linux-2.11f-11.7.1.i386.rpm ia64: ftp://updates.redhat.com/7.1/en/os/ia64/util-linux-2.11f-11.7.1.ia64.rpm Red Hat Linux 7.2: SRPMS: ftp://updates.redhat.com/7.2/en/os/SRPMS/util-linux-2.11f-12.src.rpm i386: ftp://updates.redhat.com/7.2/en/os/i386/util-linux-2.11f-12.i386.rpm ______________________________________________________________________________ [****** Begin Red Hat Bulletin ******] --------------------------------------------------------------------- Red Hat, Inc. Red Hat Security Advisory Synopsis: New util-linux packages available to fix /bin/login pam problem Advisory ID: RHSA-2001:132-04 Issue date: 2001-10-11 Updated on: 2001-10-16 Product: Red Hat Linux Keywords: login pam pam_limits Cross references: Obsoletes: RHSA-2001:095-04 --------------------------------------------------------------------- 1. Topic: New util-linux packages are available that fix a problem with /bin/login's PAM implementation. This could, in some non-default setups, cause users to receive credentials of other users. It is recommended that all users update to the fixed packages. 2001-10-22: Packages are now available for Red Hat Linux 7.2. Notably, these packages also fix the problem noted in RHSA-2001:095-04 (vipw incorrectly setting permissions on some files) - this bug was accidentally reintroduced in Red Hat Linux 7.2. 2. Relevant releases/architectures: Red Hat Linux 7.1 - alpha, i386, ia64 Red Hat Linux 7.2 - i386 3. Problem description: A problem existed in /bin/login's PAM implementation; it stored the value of a static pwent buffer across PAM calls; when used with some PAM modules in non-default configuration (such as pam_limits), it would overwrite the buffer, causing a user to get credentials of another user. Thanks go to Tarhon-Onu Victor for bringing the problem to our attention, and to Olaf Kirch for providing the patch. 4. Solution: Before applying this update, make sure all previously released errata relevant to your system have been applied. To update all RPMs for your particular architecture, run: rpm -Fvh [filenames] where [filenames] is a list of the RPMs you wish to upgrade. Only those RPMs which are currently installed will be updated. Those RPMs which are not installed but included in the list will not be updated. Note that you can also use wildcards (*.rpm) if your current directory *only* contains the desired RPMs. Please note that this update is also available via Red Hat Network. Many people find this an easier way to apply updates. To use Red Hat Network, launch the Red Hat Update Agent with the following command: up2date This will start an interactive process that will result in the appropriate RPMs being upgraded on your system. 5. Bug IDs fixed (http://bugzilla.redhat.com/bugzilla for more info): 51646 - pam limits drops other user privileges 6. RPMs required: Red Hat Linux 7.1: SRPMS: ftp://updates.redhat.com/7.1/en/os/SRPMS/util-linux-2.11f-11.7.1.src.rpm alpha: ftp://updates.redhat.com/7.1/en/os/alpha/util-linux-2.11f-11.7.1.alpha.rpm i386: ftp://updates.redhat.com/7.1/en/os/i386/util-linux-2.11f-11.7.1.i386.rpm ia64: ftp://updates.redhat.com/7.1/en/os/ia64/util-linux-2.11f-11.7.1.ia64.rpm Red Hat Linux 7.2: SRPMS: ftp://updates.redhat.com/7.2/en/os/SRPMS/util-linux-2.11f-12.src.rpm i386: ftp://updates.redhat.com/7.2/en/os/i386/util-linux-2.11f-12.i386.rpm 7. Verification: MD5 sum Package Name -------------------------------------------------------------------------- db33b22f50978471a25fd5cc973f8f54 7.1/en/os/SRPMS/util-linux-2.11f-11.7.1.src.rpm d55f6ec42e3c0268f2ab4decb24deb53 7.1/en/os/alpha/util-linux-2.11f-11.7.1.alpha.rpm 2bf1db1cadc50f783220f70aa2b7a09c 7.1/en/os/i386/util-linux-2.11f-11.7.1.i386.rpm 568c4ec61cb9cc0ebd6313fb14d0419c 7.1/en/os/ia64/util-linux-2.11f-11.7.1.ia64.rpm 3b5448a60fa6cb5580eb690a303827a5 7.2/en/os/SRPMS/util-linux-2.11f-12.src.rpm c0f329c070e416fbb20c97670199d3fe 7.2/en/os/i386/util-linux-2.11f-12.i386.rpm These packages are GPG signed by Red Hat, Inc. for security. Our key is available at: http://www.redhat.com/about/contact/pgpkey.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: Copyright(c) 2000, 2001 Red Hat, Inc. [****** End Red Hat Bulletin ******] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Red Hat, Inc. for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Center, 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 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org 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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