Date: Wed, 12 Sep 2018 05:43:09 +0000 (UTC) From: FreeBSD Security Advisories <security-advisories@freebsd.org> To: FreeBSD Security Advisories <security-advisories@freebsd.org> Subject: [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-18:12.elf Message-ID: <20180912054309.61C6B13269@freefall.freebsd.org>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-18:12.elf Security Advisory The FreeBSD Project Topic: Improper ELF header parsing Category: core Module: kernel Announced: 2018-09-12 Credits: Thomas Barabosch, Fraunhofer FKIE; Mark Johnston Affects: All supported versions of FreeBSD. Corrected: 2018-09-12 05:02:11 UTC (stable/11, 11.1-STABLE) 2018-09-12 05:07:35 UTC (releng/11.2, 11.2-RELEASE-p3) 2018-09-12 05:07:35 UTC (releng/11.1, 11.1-RELEASE-p14) 2018-09-12 05:03:30 UTC (stable/10, 10.4-STABLE) 2018-09-12 05:07:35 UTC (releng/10.4, 10.4-RELEASE-p12) CVE Name: CVE-2018-6924 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.FreeBSD.org/>. I. Background To execute a binary the kernel must parse the ELF header to determine the entry point address, the program interpreter, and other parameters. II. Problem Description Insufficient validation was performed in the ELF header parser, and malformed or otherwise invalid ELF binaries were not rejected as they should be. III. Impact Execution of a malicious ELF binary may result in a kernel crash or may disclose kernel memory. IV. Workaround No workaround is available. V. Solution Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date, and reboot. 1) To update your vulnerable system via a binary patch: Systems running a RELEASE version of FreeBSD on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install # shutdown -r +30 "Rebooting for security update" 2) To update your vulnerable system via a source code patch: The following patches have been verified to apply to the applicable FreeBSD release branches. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch https://security.FreeBSD.org/patches/SA-18:12/elf.patch # fetch https://security.FreeBSD.org/patches/SA-18:12/elf.patch.asc # gpg --verify elf.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in <URL:https://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/10/ r338605 releng/10.4/ r338606 stable/11/ r338604 releng/11.1/ r338606 releng/11.2/ r338606 - ------------------------------------------------------------------------- To see which files were modified by a particular revision, run the following command, replacing NNNNNN with the revision number, on a machine with Subversion installed: # svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base Or visit the following URL, replacing NNNNNN with the revision number: <URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-6924> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-18:12.elf.asc> -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAluYoK9fFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEZD MEU4NzhBRTVBRkU3ODgwMjhENjM1NUQzOTc5MkY0OUVBN0U1QzIACgkQ05eS9J6n 5cKA+BAApeUtPHpy5mEHC8ftJ+3NZpfI8gcfuPE0dlJi6CpXq8/ruXN5Yt5X0E0l hlbNGqEMckfe3F81rCXLbtu0zeAnSBfAFcm9xSBa6aSRfP4GAZtKDKwilPqqT9F8 sOrPR/mAfxWmWcfDt8ggAx6akr2Tt48t7TiBP/kA14+CzVmp/pMU/ceFDLk8JYjY PQzVM4fHC5xeBWtA2JjMNHnhR6XMeiDOLkgeRiRW1LhB/OwWwcb0uzVixxR34mCT vFm1eJteAitoVclgnI//GkzZZ6b7SZkqyqODWKVLWXaYgb8/Z6SaKAQm2TWuHPEh nzIpPGhnXZc+36Nn9/HYDKVn3skD1sYAnTMgPcUYZH3KfkohvFdHlnoGqkcnMwTy mSKkQx9ojuLfwot7tyJCbgU/6e82ed1g9EiFZXwW8x4ePClaAvrDozz0QGwlXgyY 1jBbFp/gYznhxTetVRHo5ug5SHZgD2Ye46TCoglHX0CprhkWwpKenoCEyfyjlHXH uI+RPd46TlQfuK4bqURRpWvNWprXGqQ0ypFVW2JJgqLPBX0QS79gzqO++C8tRqQv e16mqzBGNIre/8FOCBpV/Z61NgxqeYo2ndHxc9VTMiFXK/2v3TDK9AvYZ1/xEvwC IRpC+qo870B5XT/ihC/KpYI4jgM2/pK/Mdez6Q4s5M6eeCBHAgw= =J/a5 -----END PGP SIGNATURE-----
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