FreeBSD Security Advisory FreeBSD-SA-17:01.openssh
11 January, 2017 by firstname.lastname@example.org | freebsd
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-17:01.openssh Security Advisory The FreeBSD Project Topic: OpenSSH multiple vulnerabilities Category: contrib Module: OpenSSH Announced: 2017-01-11 Affects: All supported versions of FreeBSD. Corrected: 2017-01-11 05:56:40 UTC (stable/11, 11.0-STABLE) 2017-01-11 06:01:23 UTC (releng/11.0, 11.0-RELEASE-p7) 2017-01-11 05:56:40 UTC (stable/10, 10.3-STABLE) 2017-01-11 06:01:23 UTC (releng/10.3, 10.3-RELEASE-p16) CVE Name: CVE-2016-10009, CVE-2016-10010 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 OpenSSH is an implementation of the SSH protocol suite, providing an encrypted and authenticated transport for a variety of services, including remote shell access. OpenSSH supports accessing keys provided by a PKCS#11 token. II. Problem Description The ssh-agent(1) agent supports loading a PKCS#11 module from outside a trusted whitelist. An attacker can request loading of a PKCS#11 module across forwarded agent-socket. [CVE-2016-10009] When privilege separation is disabled, forwarded Unix domain sockets would be created by sshd(8) with the privileges of 'root' instead of the authenticated user. [CVE-2016-10010] III. Impact A remote attacker who have control of a forwarded agent-socket on a remote system and have the ability to write files on the system running ssh-agent(1) agent can run arbitrary code under the same user credential. Because the attacker must already have some control on both systems, it is relatively hard to exploit this vulnerability in a practical attack. [CVE-2016-10009] When privilege separation is disabled (on FreeBSD, privilege separation is enabled by default and has to be explicitly disabled), an authenticated attacker can potentially gain root privileges on systems running OpenSSH server. [CVE-2016-10010] IV. Workaround Systems not running ssh-agent(1) and sshd(8) services are not affected. System administrators may remove ssh-agent(1) to mitigate CVE-2016-10009. System administrators should enable privilege separation when running OpenSSH server, which is the FreeBSD default, to mitigate CVE-2016-10010. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. Kill all running ssh-agent(1) process and restart sshd(8) service. A reboot is recommended but not required. 2) 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 Kill all running ssh-agent(1) process and restart sshd(8) service. A reboot is recommended but not required. 3) 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-17:01/openssh.patch # fetch https://security.FreeBSD.org/patches/SA-17:01/openssh.patch.asc # gpg --verify openssh.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 <URL:https://www.FreeBSD.org/handbook/makeworld.html>. Kill all running ssh-agent(1) process and restart sshd(8) service. A reboot is recommended but not required. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/10/ r311915 releng/10.3/ r311916 stable/11/ r311915 releng/11.0/ r311916 - ------------------------------------------------------------------------- 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://www.openssh.com/txt/release-7.4> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-10009> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-10010> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-17:01.openssh.asc> -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.1.16 (FreeBSD) iQIzBAEBCgAdFiEEHPf/b631yp++G4yy7Wfs1l3PaucFAlh1yuAACgkQ7Wfs1l3P auebFA//TGtwrub7JNTgKdc5qnpw+s8W1j0AnQ4wTaJ6v7zNyUB0DG+LHW4uXCwR xc9Etd2mhY26wJIUxx0Z3oArcqVBGpCGbozuIOU6AdgmHdOL3ddj8aq4SuC0PyMA 0OvNgZIRPZxEm81MP+6/GES4JLmOumiNeAG/MrtITGJDP/K5vVPIst/+F7OJ4P2+ OGrjqBWmAz2EMG62QUJI8oSwB+FJpXtWHKOC4fPGibAQe3vF1WequbcDkLsYl1pX Ktlk/qh9ivaQreM9rHkUDF0PYwFdsXzveze/TLNbEo+w43v/PAlyR+xw2+22VjGK fxTL8Gk2tMQfahGZwFmmQFPLcwNRcdjgnZcRRHA3z8vKgM831A53gV3KskUwZl4V DyKdXtl44zrZ7PtPJ1gJkPK6B8zzfjnSwzPC51pDjh30ps28Rgfc6JOyjxhX5BJ4 sXvQ3meiEfVgVq3DpTqQ3mZVQ1pRF+yhPf1Ptts9fQzAD95JsFF0WT0nzbYoB2VY KrU4V7d/Ys+HIeQWgDwZlFuLOULlVZDW/H55PT5Tx9JvP5vRlZS/w2HHN7wwy8n5 tNX9mcH8DuG7X/jWDR9ompbJp5uZqcKWVMHPQY7fnaLSJoQMqrpPgZ9tsw6wq347 Vslm3qQwUTSGRagH0rBuHiVJmY/AeqY3lvsaZklWGIYMRjmUeA0= =3z/p -----END PGP SIGNATURE----- _______________________________________________ email@example.com mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-announce To unsubscribe, send any mail to "firstname.lastname@example.org"