FreeBSD Security Advisory FreeBSD-SA-13:10.sctp

Fabricante: FreeBSD
Fecha: 22/08/2013
Identificador: FreeBSD-SA-13:10.sctp
FreeBSD Security Advisory FreeBSD-SA-13:10.sctp
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ============================================================================= FreeBSD-SA-13:10.sctp Security Advisory The FreeBSD Project Topic: Kernel memory disclosure in sctp(4) Category: core Module: sctp Announced: 2013-08-22 Credits: Julian Seward, Michael Tuexen Affects: All supported versions of FreeBSD. Corrected: 2013-08-15 04:25:16 UTC (stable/9, 9.2-PRERELEASE) 2013-08-15 05:14:20 UTC (releng/9.2, 9.2-RC2) 2013-08-22 00:51:48 UTC (releng/9.1, 9.1-RELEASE-p6) 2013-08-15 04:35:25 UTC (stable/8, 8.4-STABLE) 2013-08-22 00:51:56 UTC (releng/8.4, 8.4-RELEASE-p3) 2013-08-22 00:51:56 UTC (releng/8.3, 8.3-RELEASE-p10) CVE Name: CVE-2013-5209 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background The SCTP protocol provides reliable, flow-controlled, two-way transmission of data. It is a message oriented protocol and can support the SOCK_STREAM and SOCK_SEQPACKET abstractions. The SCTP protocol checks the integrity of messages by validating the state cookie information that is returned from the peer. II. Problem Description When initializing the SCTP state cookie being sent in INIT-ACK chunks, a buffer allocated from the kernel stack is not completely initialized. III. Impact Fragments of kernel memory may be included in SCTP packets and transmitted over the network. For each SCTP session, there are two separate instances in which a 4-byte fragment may be transmitted. This memory might contain sensitive information, such as portions of the file cache or terminal buffers. This information might be directly useful, or it might be leveraged to obtain elevated privileges in some way. For example, a terminal buffer might include an user-entered password. IV. Workaround No workaround is available, but systems not using the SCTP protocol are not vulnerable. 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. 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. # fetch http://security.FreeBSD.org/patches/SA-13:10/sctp.patch # fetch http://security.FreeBSD.org/patches/SA-13:10/sctp.patch.asc # gpg --verify sctp.patch.asc b) Apply the patch. # cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in and reboot the system. 3) 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 VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/8/ r254354 releng/8.3/ r254632 releng/8.4/ r254632 stable/9/ r254352 releng/9.1/ r254631 releng/9.2/ r254355 - ------------------------------------------------------------------------- To see which files were modified by a particular revision, run the following command, replacing XXXXXX with the revision number, on a machine with Subversion installed: # svn diff -cXXXXXX --summarize svn://svn.freebsd.org/base Or visit the following URL, replacing XXXXXX with the revision number: VII. References The latest revision of this advisory is available at -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.21 (FreeBSD) iEYEARECAAYFAlIVY1YACgkQFdaIBMps37L0AQCgh30FZd+f+rmzMabRFkTPVEmX tZgAnRuZptKgvlHkqnEhUj30tH6xLDCO =KJ8k -----END PGP SIGNATURE-----