From bugzilla@redhat.com Mon Jul 29 16:55:26 2002 From: bugzilla@redhat.com To: redhat-watch-list@redhat.com, redhat-announce-list@redhat.com Cc: bugtraq@securityfocus.com Date: Mon, 29 Jul 2002 11:01 -0400 Subject: [RHSA-2002:132-14] Updated util-linux package fixes password locking race [The following text is in the "iso-8859-1" character set] [Your display is set for the "US-ASCII" character set] [Some characters may be displayed incorrectly] --------------------------------------------------------------------- Red Hat, Inc. Red Hat Security Advisory Synopsis: Updated util-linux package fixes password locking race Advisory ID: RHSA-2002:132-14 Issue date: 2002-06-27 Updated on: 2002-07-29 Product: Red Hat Linux Keywords: util-linux password locking race Cross references: Obsoletes: CVE Names: CAN-2002-0638 --------------------------------------------------------------------- 1. Topic: A locally exploitable vulnerability is present in the util-linux package shipped with Red Hat Linux 2. Relevant releases/architectures: Red Hat Linux 6.2 - alpha, i386, sparc Red Hat Linux 7.0 - alpha, i386 Red Hat Linux 7.1 - alpha, i386, ia64 Red Hat Linux 7.2 - i386, ia64 Red Hat Linux 7.3 - i386 3. Problem description: The util-linux package contains a large variety of low-level system utilities that are necessary for a Linux system to function. The 'chfn' utility included in this package allows users to modify personal information stored in the system-wide password file, /etc/passwd. In order to modify this file, this application is installed setuid root. Under certain conditions, a carefully crafted attack sequence can be performed to exploit a complex file locking and modification race present in this utility allowing changes to be made to /etc/passwd. In order to successfully exploit the vulnerability and perform privilege escalation there is a need for a minimal administrator interaction. Additionally, the password file must be over 4 kilobytes, and the local attackers entry must not be in the last 4 kilobytes of the password file. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2002-0638 to this issue. An interim workaround is to remove setuid flags from /usr/bin/chfn and /usr/bin/chsh. All users of Red Hat Linux should update to the errata util-linux packages which contain a patch to correct this vulnerability. Many thanks to Michal Zalewski of Bindview for alerting us to this issue. 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): 6. RPMs required: Red Hat Linux 6.2: SRPMS: ftp://updates.redhat.com/6.2/en/os/SRPMS/util-linux-2.10f-7.6.2.src.rpm alpha: ftp://updates.redhat.com/6.2/en/os/alpha/util-linux-2.10f-7.6.2.alpha.rpm i386: ftp://updates.redhat.com/6.2/en/os/i386/util-linux-2.10f-7.6.2.i386.rpm sparc: ftp://updates.redhat.com/6.2/en/os/sparc/util-linux-2.10f-7.6.2.sparc.rpm Red Hat Linux 7.0: SRPMS: ftp://updates.redhat.com/7.0/en/os/SRPMS/util-linux-2.10m-12.7.0.src.rpm alpha: ftp://updates.redhat.com/7.0/en/os/alpha/util-linux-2.10m-12.7.0.alpha.rpm i386: ftp://updates.redhat.com/7.0/en/os/i386/util-linux-2.10m-12.7.0.i386.rpm Red Hat Linux 7.1: SRPMS: ftp://updates.redhat.com/7.1/en/os/SRPMS/util-linux-2.11f-17.7.2.src.rpm alpha: ftp://updates.redhat.com/7.1/en/os/alpha/util-linux-2.11f-17.7.2.alpha.rpm i386: ftp://updates.redhat.com/7.1/en/os/i386/util-linux-2.11f-17.7.2.i386.rpm ia64: ftp://updates.redhat.com/7.1/en/os/ia64/util-linux-2.11f-17.7.2.ia64.rpm Red Hat Linux 7.2: SRPMS: ftp://updates.redhat.com/7.2/en/os/SRPMS/util-linux-2.11f-17.7.2.src.rpm i386: ftp://updates.redhat.com/7.2/en/os/i386/util-linux-2.11f-17.7.2.i386.rpm ia64: ftp://updates.redhat.com/7.2/en/os/ia64/util-linux-2.11f-17.7.2.ia64.rpm Red Hat Linux 7.3: SRPMS: ftp://updates.redhat.com/7.3/en/os/SRPMS/util-linux-2.11n-12.7.3.src.rpm i386: ftp://updates.redhat.com/7.3/en/os/i386/util-linux-2.11n-12.7.3.i386.rpm ftp://updates.redhat.com/7.3/en/os/i386/mount-2.11n-12.7.3.i386.rpm ftp://updates.redhat.com/7.3/en/os/i386/losetup-2.11n-12.7.3.i386.rpm 7. Verification: MD5 sum Package Name -------------------------------------------------------------------------- 0af6265f350849394fc54ca7f006fd82 6.2/en/os/SRPMS/util-linux-2.10f-7.6.2.src.rpm 4e30115e7fd311ac8496637c03716473 6.2/en/os/alpha/util-linux-2.10f-7.6.2.alpha.rpm e1c0e740d41aaddc7817604ed449e872 6.2/en/os/i386/util-linux-2.10f-7.6.2.i386.rpm fe28b4c80b9fe909c38f913b899ddb16 6.2/en/os/sparc/util-linux-2.10f-7.6.2.sparc.rpm 4aa3502469cc8255aea825cebe82d4db 7.0/en/os/SRPMS/util-linux-2.10m-12.7.0.src.rpm b2e1b30a837e440297acba35d13fab77 7.0/en/os/alpha/util-linux-2.10m-12.7.0.alpha.rpm af9aca214e81e4f306d49ed398a79f22 7.0/en/os/i386/util-linux-2.10m-12.7.0.i386.rpm dc87f0566da2f6a37443f9614cb1ff61 7.1/en/os/SRPMS/util-linux-2.11f-17.7.2.src.rpm c3bc4100fdc6e4e7c4b524c16991f168 7.1/en/os/alpha/util-linux-2.11f-17.7.2.alpha.rpm 668e4b28b07dcd9718744b2c59383bc2 7.1/en/os/i386/util-linux-2.11f-17.7.2.i386.rpm 200e1661f445fca662f51d810f650448 7.1/en/os/ia64/util-linux-2.11f-17.7.2.ia64.rpm dc87f0566da2f6a37443f9614cb1ff61 7.2/en/os/SRPMS/util-linux-2.11f-17.7.2.src.rpm 668e4b28b07dcd9718744b2c59383bc2 7.2/en/os/i386/util-linux-2.11f-17.7.2.i386.rpm 200e1661f445fca662f51d810f650448 7.2/en/os/ia64/util-linux-2.11f-17.7.2.ia64.rpm 474988909a18c0f73a65de40bf946e92 7.3/en/os/SRPMS/util-linux-2.11n-12.7.3.src.rpm b1b6d7852f75d1014204b7853f656427 7.3/en/os/i386/losetup-2.11n-12.7.3.i386.rpm 496ec0a9c0720ba5bed7baa917114aac 7.3/en/os/i386/mount-2.11n-12.7.3.i386.rpm da8c81ee48c180694b89c9c99f543256 7.3/en/os/i386/util-linux-2.11n-12.7.3.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: http://www.kb.cert.org/vuls/id/405955 http://razor.bindview.com/publish/advisories/adv_chfn.html http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-0638 Copyright(c) 2000, 2001, 2002 Red Hat, Inc.