FreeBSD Security Advisory FreeBSD-SA-16:01.sctp

Fabricante: FreeBSD
Fecha: 14/01/2016
Identificador: FreeBSD-SA-16:01.sctp
FreeBSD Security Advisory FreeBSD-SA-16:01.sctp
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-16:01.sctp Security Advisory The FreeBSD Project Topic: SCTP ICMPv6 error message vulnerability Category: core Module: SCTP Announced: 2016-01-14 Credits: Jonathan T. Looney 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-2016-1879 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background The Stream Control Transmission Protocol (SCTP) protocol provides reliable, flow-controlled, two-way transmission of data. The Internet Control Message Protocol for IPv6 (ICMPv6) provides a way for hosts on the Internet to exchange control information. Among other uses, a host or router can use ICMPv6 to inform a host when there is an error delivering a packet sent by that host. II. Problem Description A lack of proper input checks in the ICMPv6 processing in the SCTP stack can lead to either a failed kernel assertion or to a NULL pointer dereference. In either case, a kernel panic will follow. III. Impact A remote, unauthenticated attacker can reliably trigger a kernel panic in a vulnerable system running IPv6. Any kernel compiled with both IPv6 and SCTP support is vulnerable. There is no requirement to have an SCTP socket open. IPv4 ICMP processing is not impacted by this vulnerability. IV. Workaround No workaround is available, but systems using a kernel compiled without SCTP support or IPv6 support are not vulnerable. In addition, some stateful firewalls may block ICMPv6 messages that are not responding to a legitimate connection. (However, this may not completely block the problem, as an ICMPv6 message could still be sent in response to a legitimate SCTP connection.) 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. Rebooting to the new kernel is 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 Rebooting to the new kernel is 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-16:01/sctp.patch # fetch https://security.FreeBSD.org/patches/SA-16:01/sctp.patch.asc # gpg --verify sctp.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 and reboot the system. 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----- iQIcBAEBCgAGBQJWl2j1AAoJEO1n7NZdz2rnIfoQAOZTLX3VovQPGj9wr7PspLQi Tazu6vRnjzdOdjpeWwSgYlq6DJGjT71c/BRyCWCoijr2uyBWRlANqzMO64thuTzx gc6juRlChLDF4sNVWbNDMRwuHTfCpgDH2/4hQeR/9CmiQxHJyqL0gXc889D206i9 KzgmYrSALEVK0E2kDBeRMsadtqPIEzCw4LygWd4qrtYNPjAfBR/a9U4rg7ZN0ICZ RCPnkAF6qI09B931QfHaI4C9wdBF8DJ6nKN/2aU9ATdOJJb7oUkpaHht8kmbdZS+ Tn12nEXkQvNxuAKT7Fb87M14s7LUR12V5wgDeMd2UtOfkeSpGEDFACdhYW3IpKan gD+2IlzLRhoQTJ7lQWMRTKh3OiDDR2kLwvbEU7BGecDSG6fVkgumn6NlHYybdH7L axpDOxPz8ITfcdRipIXLOQEC308ckdmaEwqi4ikgBGwEkSgIwj1flGStswvcMrim vT0xof2dv1y6RW5xYnJF7Mtn/rEcqrql/BeBp/kxJZ2Qt3hkppQnjWD6kvrEj00s CajzxdBTM7J3buDzu++RL2GL9p5Cwo1kDmUJdWimIbSecL62J9+PwFCDYp/dOy25 GAPGnf7gk8YhwM8pHwLtcX0b9UundkXLWnLBN7R12fL7Ch2CmPbgPcoFc5CSbcIx TBRU+4TGcNGxigXyzIHT =G0DD -----END PGP SIGNATURE-----