__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Center ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Red Hat LPRng Vulnerability [Red Hat Security Advisory 2001:077-05] June 14, 2001 20:00 GMT Number L-096 ______________________________________________________________________________ PROBLEM: At init time LPRng fails to drop supplemental group memberships when it drops uid and gid. PLATFORM: Red Hat Linux 7.0 - alpha and i386 Red Hat Linux 7.1 - i386 DAMAGE: When LPRng drops uid and gid it fails to drop any supplemental group memberships. LPRng and its children maintain any supplemental groups that the process starting LPRng had at start time. It is possible to exploit this to gain access to groups that would allow more privileges on the system. SOLUTION: Apply patch as described below. ______________________________________________________________________________ VULNERABILITY The risk is LOW: Although it poses a security risk there are ASSESSMENT: currently no known exploits using this vulnerability. ______________________________________________________________________________ [****** Start Red Hat Security Advisory ******] --------------------------------------------------------------------- Red Hat, Inc. Red Hat Security Advisory Synopsis: LPRng fails to drop supplemental group membership Advisory ID: RHSA-2001:077-05 Issue date: 2001-06-07 Updated on: 2001-06-11 Product: Red Hat Linux Keywords: LPRng groups Cross references: Obsoletes: RHBA-2001:039-05 RHSA-2000:065-06 --------------------------------------------------------------------- 1. Topic: When LPRng drops uid and gid, it fails to drop membership in its supplemental groups. 2. Relevant releases/architectures: Red Hat Linux 7.0 - alpha, i386 Red Hat Linux 7.1 - i386 3. Problem description: LPRng fails to drop supplemental group membership at init time, though it does properly setuid and setgid. The result is that LPRng, and its children, maintain any supplemental groups that the process starting LPRng had at the time it started LPRng. This is a security risk. 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): 43341 - lpd fails to drop groups of root 6. RPMs required: Red Hat Linux 7.0: SRPMS: ftp://updates.redhat.com/7.0/en/os/SRPMS/LPRng-3.7.4-23.src.rpm alpha: ftp://updates.redhat.com/7.0/en/os/alpha/LPRng-3.7.4-23.alpha.rpm i386: ftp://updates.redhat.com/7.0/en/os/i386/LPRng-3.7.4-23.i386.rpm Red Hat Linux 7.1: SRPMS: ftp://updates.redhat.com/7.1/en/os/SRPMS/LPRng-3.7.4-23.src.rpm i386: ftp://updates.redhat.com/7.1/en/os/i386/LPRng-3.7.4-23.i386.rpm 7. Verification: MD5 sum Package Name -------------------------------------------------------------------------- 9a9a148f44c80cb83a1cc53b7fc60492 7.0/en/os/SRPMS/LPRng-3.7.4-23.src.rpm 3a83c1cdf9eef8bbc72bd511264a0fc3 7.0/en/os/alpha/LPRng-3.7.4-23.alpha.rpm 23e85c03c49b6d1eda0a76428f181dc5 7.0/en/os/i386/LPRng-3.7.4-23.i386.rpm 9a9a148f44c80cb83a1cc53b7fc60492 7.1/en/os/SRPMS/LPRng-3.7.4-23.src.rpm 23e85c03c49b6d1eda0a76428f181dc5 7.1/en/os/i386/LPRng-3.7.4-23.i386.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: Copyright(c) 2000, 2001 Red Hat, Inc. [****** End Red Hat Security Advisory ******] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Red Hat Linux 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. 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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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