__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Updated PAM Packages [Red Hat RHSA-2004:304-05] August 19, 2004 12:00 GMT Number O-200 ______________________________________________________________________________ PROBLEM: There is a potential security problem present in the pam_wheel module and a bug in the pam_lastlog module which prevents it from properly manipulating the /var/log/lastlog entry for users with very high user IDs. PLATFORM: Red Hat Enterprise Linux AS (v.2.1) Red Hat Enterprise Linux ES (v.2.1) Red Hat Enterprise Linux WS (v.2.1) Red Hat Linux Advanced Workstation 2.1 for the Itanium Processor DAMAGE: If the pam_wheel module was used with the "trust" option enabled, but without the "use_uid" option, any local user would be able to spoof the username returned by getlogin() and gain access to the superuser account without supplying a password. SOLUTION: Upgrade to the appropriate package. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. A local user could get root access. ASSESSMENT: ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/o-200.shtml ORIGINAL BULLETIN: https://rhn.redhat.com/errata/RHSA-2004-304.html CVE/CAN: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name= CVE-2003-0388 ______________________________________________________________________________ [***** Start Red Hat RHSA-2004:304-05 *****] Updated pam packages Advisory: RHSA-2004:304-05 Last updated on: 2004-08-18 Affected Products: Red Hat Enterprise Linux AS (v. 2.1) Red Hat Enterprise Linux ES (v. 2.1) Red Hat Enterprise Linux WS (v. 2.1) Red Hat Linux Advanced Workstation 2.1 for the Itanium Processor CVEs (cve.mitre.org): CAN-2003-0388 Security Advisory Details: Updated pam packages that fix a security vulnerability are now available for Red Hat Enterprise Linux 2.1. PAM (Pluggable Authentication Modules) is a system security tool that allows system administrators to set an authentication policy without having to recompile programs that handle authentication. These updates fix a potential security problem present in the pam_wheel module. These updates correct a bug in the pam_lastlog module which prevented it from properly manipulating the /var/log/lastlog entry for users with very high user IDs. The pam_wheel module is used to restrict access to a particular service based on group membership. If the pam_wheel module was used with the "trust" option enabled, but without the "use_uid" option, any local user would be able to spoof the username returned by getlogin(). The user could therefore gain access to a superuser account without supplying a password. In Red Hat Enterprise Linux 2.1, pam_wheel is not used by default. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2003-0388 to this issue. When manipulating the entry in /var/log/lastlog, which corresponds to a given user, the pam_lastlog module calculates the location of the entry by multiplying the UID and the length of an entry in the file. On some systems, the result of this calculation would mistakenly be truncated to 32 bits for users with sufficiently high UIDs. All users of pam should upgrade to these updated packages, which resolve these issues. Updated packages: Red Hat Enterprise Linux AS (v. 2.1) -------------------------------------------------------------------------------- SRPMS: pam-0.75-46.9.src.rpm 5c78062a595e3443d22ca145b774cd34 i386: pam-0.75-46.9.i386.rpm 1a72acefcb8b2c7bfb875f9024ae818b pam-devel-0.75-46.9.i386.rpm e129fb8519d309ab26d3045bd91bb2e3 ia64: pam-0.75-46.9.ia64.rpm 851a5e5a7f78b4a4cbde060c62ab1e7d pam-devel-0.75-46.9.ia64.rpm 3b23b14f7cfbcf2a73d21fd3a0b18bda Red Hat Enterprise Linux ES (v. 2.1) -------------------------------------------------------------------------------- SRPMS: pam-0.75-46.9.src.rpm 5c78062a595e3443d22ca145b774cd34 i386: pam-0.75-46.9.i386.rpm 1a72acefcb8b2c7bfb875f9024ae818b pam-devel-0.75-46.9.i386.rpm e129fb8519d309ab26d3045bd91bb2e3 Red Hat Enterprise Linux WS (v. 2.1) -------------------------------------------------------------------------------- SRPMS: pam-0.75-46.9.src.rpm 5c78062a595e3443d22ca145b774cd34 i386: pam-0.75-46.9.i386.rpm 1a72acefcb8b2c7bfb875f9024ae818b pam-devel-0.75-46.9.i386.rpm e129fb8519d309ab26d3045bd91bb2e3 Red Hat Linux Advanced Workstation 2.1 for the Itanium Processor -------------------------------------------------------------------------------- SRPMS: pam-0.75-46.9.src.rpm 5c78062a595e3443d22ca145b774cd34 ia64: pam-0.75-46.9.ia64.rpm 851a5e5a7f78b4a4cbde060c62ab1e7d pam-devel-0.75-46.9.ia64.rpm 3b23b14f7cfbcf2a73d21fd3a0b18bda (The unlinked packages above are only available from the Red Hat Network) Solution Before applying this update, make sure that all previously-released errata relevant to your system have been applied. Use Red Hat Network to download and update your packages. To launch the Red Hat Update Agent, use the following command: up2date For information on how to install packages manually, refer to the following Web page for the System Administration or Customization guide specific to your system: http://www.redhat.com/docs/manuals/enterprise/ Bugs fixed: (see bugzilla for more information) 98826 - CAN-2003-0388 pam_wheel uses getlogin in insecure fashion References: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0388 Keywords: pam, pam_lastlog, pam_wheel -------------------------------------------------------------------------------- The listed packages are GPG signed by Red Hat, Inc. for security. Our key is available at: http://www.redhat.com/solutions/security/news/publickey/#key You can verify each package and see who signed it with the following command: rpm --checksig -v filename If you only wish to verify that each package has not been corrupted or tampered with, examine only the md5sum with the following command: md5sum filename The Red Hat security contact is security@redhat.com. More contact details at http://www.redhat.com/solutions/security/news/contact.html [***** End Red Hat RHSA-2004:304-05 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Red Hat 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 (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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