-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-16:30.portsnap Security Advisory The FreeBSD Project Topic: Multiple portsnap vulnerabilities Category: core Module: portsnap Announced: 2016-10-10 Affects: All supported versions of FreeBSD. Corrected: 2016-09-28 21:33:35 UTC (stable/11, 11.0-STABLE) 2016-09-28 22:04:07 UTC (releng/11.0, 11.0-RELEASE-p1) 2016-10-05 00:33:06 UTC (stable/10, 10.3-STABLE) 2016-10-10 07:18:54 UTC (releng/10.3, 10.3-RELEASE-p10) 2016-10-10 07:18:54 UTC (releng/10.2, 10.2-RELEASE-p23) 2016-10-10 07:18:54 UTC (releng/10.1, 10.1-RELEASE-p40) 2016-10-05 01:01:10 UTC (stable/9, 9.3-STABLE) 2016-10-10 07:19:16 UTC (releng/9.3, 9.3-RELEASE-p48) For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background The portsnap utility is used to fetch and update compressed snapshots of the FreeBSD ports tree. Portsnap fetches snapshots and updates over http, and then cryptographically verifies the downloaded files. II. Problem Description Flaws in portsnap's verification of downloaded tar files allows additional files to be included without causing the verification to fail. Portsnap may then use or execute these files. III. Impact An attacker who can conduct man in the middle attack on the network at the time when portsnap is run can cause portsnap to execute arbitrary commands under the credentials of the user who runs portsnap, typically root. IV. Workaround The ports tree may be obtained by methods other than portsnap, as described in the FreeBSD handbook. V. Solution portsnap has been modified to explicitly validate compressed files within the tar file by full name, rather than relying on gunzip's filename search logic. portsnap now verifies that snapshots contain only the expected files. Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. No reboot is needed. Perform one of the following: 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. This advisory is released concurrently with FreeBSD-SA-16:29.bspatch which contains special instructions for using freebsd-update. Following the instructions in that advisory will safely apply updates for FreeBSD-SA-16:29.bspatch, FreeBSD-SA-16:30.portsnap, and FreeBSD-SA-16:31.libarchive. 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. [FreeBSD 10.x] # fetch https://security.FreeBSD.org/patches/SA-16:30/portsnap-10.patch # fetch https://security.FreeBSD.org/patches/SA-16:30/portsnap-10.patch.asc # gpg --verify portsnap-10.patch.asc [FreeBSD 9.3] # fetch https://security.FreeBSD.org/patches/SA-16:30/portsnap-9.3.patch # fetch https://security.FreeBSD.org/patches/SA-16:30/portsnap-9.3.patch.asc # gpg --verify portsnap-9.3.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile the operating system using buildworld and installworld as described in . VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/9/ r306701 releng/9.3/ r306942 stable/10/ r306697 releng/10.1/ r306941 releng/10.2/ r306941 releng/10.3/ r306941 stable/11/ r306418 releng/11.0/ r306419 - ------------------------------------------------------------------------- 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: VII. References The latest revision of this advisory is available at -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.1.13 (FreeBSD) iQIcBAEBCgAGBQJX+0OqAAoJEO1n7NZdz2rns54P/3N6V4ZGWZ8jXDSw7KPRhF16 gUs2AQx+rL+o5rOVsMZ6DulVtFP+AzUvEsLIJeARdaOJar9St1cQVTZHa+8CtWr5 aCSgx5r39srcvvMuQ34z0yss7eEkHRubzkIzrjHcD6MweFg4tAIufXHgxmhNVuKp QOQCwUbWIp8MssNbd/nYr1fpNoEvhkuzEv+EsvU+gTXeYNbHDS8zN/XC1a4167Q9 flFCqVn45ZpYR+2ifeLv0s+Rj4MQdnaCUYPpt1JoY5pIr/1GbNuywam9YgUQJZ7o gbY+S9Un0aByEOmPgD2e6qb8qhQFtaJgAbhB51dsI/qpZUljQKERmV1vd78drqWB 1gss/MFe5oyxZ5IbmHLBabIcKvvtH72gSaD8Zp973TbD72usjC/ZfdkukNBlWkbm M4PFTK+VQA1y5c8R2RduVoz3ioaBtRisxqqGOi0i3AUgiWx6IeP9jkIana28dGtJ Mkm4ZiWBj12lT5B+gafpy7+bLkbYl2sEFYIt+YUlJ1GqAumyDnnmYt5rDhZwMLFo 7ywCpCwtoBc49sCV7szV4MdFw0Zmo8tT0uiWBehferN1SHygKVNGnXIj+NotRXx0 mp0j7pgK4AcML2y7pJLEUwyWUKE5tBkPKmHg+4ELhqPb0mjm+A+KHX/8vXxlPpRJ 2yVhfIubEhECQJeJKAqm =y+kG -----END PGP SIGNATURE-----