FreeBSD Security Advisory FreeBSD-SA-16:06.bsnmpd

Fabricante: FreeBSD
Fecha: 14/01/2016
Identificador: FreeBSD-SA-16:06.bsnmpd
FreeBSD Security Advisory FreeBSD-SA-16:06.bsnmpd
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-16:06.bsnmpd Security Advisory The FreeBSD Project Topic: Insecure default bsnmpd.conf permissions Category: contrib Module: bsnmpd Announced: 2016-01-14 Credits: Pierre Kim Affects: All supported versions of FreeBSD. Corrected: 2016-01-14 09:11:42 UTC (stable/10, 10.2-STABLE) 2016-01-14 09:10:46 UTC (releng/10.2, 10.2-RELEASE-p9) 2016-01-14 09:11:16 UTC (releng/10.1, 10.1-RELEASE-p26) 2016-01-14 09:11:48 UTC (stable/9, 9.3-STABLE) 2016-01-14 09:11:26 UTC (releng/9.3, 9.3-RELEASE-p33) CVE Name: CVE-2015-5677 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background The bsnmpd daemon serves the Internet SNMP (Simple Network Management Protocol). It is intended to serve only the absolute basic MIBs and implements all other MIBs through loadable modules. II. Problem Description The SNMP protocol supports an authentication model called USM, which relies on a shared secret. The default permission of the bsnmpd configuration file, /etc/bsnmpd.conf, is weak and does not provide adequate protection against local unprivileged users. III. Impact A local user may be able to read the shared secret, if configured and used by the system administrator. IV. Workaround No workaround is available, but systems that do not use bsnmpd with its USM authentication model are not vulnerable. V. Solution This vulnerability can be fixed by modifying the permission on /etc/bsnmpd.conf to owner root:wheel and permission 0600. The patch is provided mainly for third party vendors who deploy FreeBSD and provide a safe default. The patch itself DOES NOT fix the permissions for existing installations. The patch can be applied by performing one of the following: 1) Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. The system administrator should change the permission on /etc/bsnmpd.conf to root:wheel and 0600. 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 The system administrator should change the permission on /etc/bsnmpd.conf to root:wheel and 0600. 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-16:06/bsnmpd.patch # fetch https://security.FreeBSD.org/patches/SA-16:06/bsnmpd.patch.asc # gpg --verify bsnmpd.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/ r293898 releng/9.3/ r293896 stable/10/ r293897 releng/10.1/ r293894 releng/10.2/ r293893 - ------------------------------------------------------------------------- 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----- iQIcBAEBCgAGBQJWl2j4AAoJEO1n7NZdz2rnkaQP/3K9kqYY1YoHQ++uzFPnfuZQ mkGPJ0frGG46pTL806QJidky6D0LP0zNCzhtU45ZlFMguJ3B3QYp/62Cw61dBG22 x0uEkvI2F2F39IPA/clspyUHg3Y1RYgTpJrxey0JLrK0yxelyI8vMwB4tCB2eEDW ZGVU6rvFQcWJOWHABXVYcc+4Yy5ucudp0QbJsVHAKLtF7MLuntVlUj+x4Nncog5k kmGt6W7tzFn2gNsWcmntmG/LWyPkPURWhYfIj3fgcRrpMTVIDFX5PTgQyJR7DwOM /beIoQxxKBUwTW1ZRgvcCqFBu7DKSCMABoHgpqLj1gdeiJ1LaO4dErtWXvdBEAAP +XLi5OkRG3OKzIAIRnkz/SrkAUoRkzHEK1dI0coyw7AdXXjDBWtX+n9lzRXs7hqT LC3riK/Km9OYVn3+T7tCWnvKN45f+FnD8zxZDE+33Jv9wI8X+CCs9GjJdoJ0HDSd b6rg8E4gGPzfwFxSNXZQKfDSSuVBECIp3av1gp6hN3qZNOX/sadMsxro8VVGFLPg 81rC+JfKNTeVtxF8oJi9eg3FQ/eupxQv4RvC2c37R7LcErAU1KKxZyNrwv6xDEMx QVnx74o+luxXSirLxq276pfBQJdMjxYzWCj6E8ztcAZenz3M4WNiRFlt7hdq/3YO bDBdQPe4eYSHHSGyGcz/ =LDPU -----END PGP SIGNATURE-----