-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ============================================================================= FreeBSD-SA-07:10.gtar Security Advisory The FreeBSD Project Topic: gtar directory traversal vulnerability Category: contrib Module: contrib_tar Announced: 2007-11-29 Credits: Dmitry V. Levinx Affects: FreeBSD 5.x releases Corrected: 2007-11-29 16:08:54 UTC (RELENG_5, 5.5-STABLE) 2007-11-29 16:09:26 UTC (RELENG_5_5, 5.5-RELEASE-p17) CVE Name: CVE-2007-4131 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background GNU tar (gtar) is a utility to create and extract "tape archives", commonly known as tar files. GNU tar is included in FreeBSD 5.x as /usr/bin/gtar. II. Problem Description Insufficient sanity checking of paths containing '.' and '..' allows gtar to overwrite arbitrary files on the system. III. Impact An attacker who can convince an user to extract a specially crafted archive can overwrite arbitrary files with the permissions of the user running gtar. If that user is root, the attacker can overwrite any file on the system. IV. Workaround Use "bsdtar", which has been the default tar implementation since FreeBSD 5.3. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 5-STABLE, or to the RELENG_5_5 security branch dated after the correction date. 2) To patch your present system: The following patches have been verified to apply to FreeBSD 5.5 systems. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch http://security.FreeBSD.org/patches/SA-07:10/gtar.patch # fetch http://security.FreeBSD.org/patches/SA-07:10/gtar.patch.asc b) Execute the following commands as root: # cd /usr/src # patch < /path/to/patch # cd /usr/src/gnu/usr.bin/tar # make obj && make depend && make && make install VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - ------------------------------------------------------------------------- RELENG_5 src/contrib/tar/src/misc.c 1.3.8.1 RELENG_5_5 src/UPDATING 1.342.2.35.2.17 src/sys/conf/newvers.sh 1.62.2.21.2.19 src/contrib/tar/src/misc.c 1.3.20.1 - ------------------------------------------------------------------------- VII. References http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-4131 The latest revision of this advisory is available at http://security.FreeBSD.org/advisories/FreeBSD-SA-07:10.gtar.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (FreeBSD) iD8DBQFHTue3FdaIBMps37IRAgzFAKCMswqo5lH2+bb0yGRN+qhPqfBYlACfQ4+j Dq8Gbv9wz/AwDyAEZq2+1eQ= =1e8b -----END PGP SIGNATURE-----