139 lines
4.9 KiB
Text
139 lines
4.9 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA1
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=============================================================================
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FreeBSD-SA-13:10.sctp Security Advisory
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The FreeBSD Project
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Topic: Kernel memory disclosure in sctp(4)
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Category: core
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Module: sctp
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Announced: 2013-08-22
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Credits: Julian Seward, Michael Tuexen
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Affects: All supported versions of FreeBSD.
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Corrected: 2013-08-15 04:25:16 UTC (stable/9, 9.2-PRERELEASE)
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2013-08-15 05:14:20 UTC (releng/9.2, 9.2-RC1-p1)
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2013-08-15 05:14:20 UTC (releng/9.2, 9.2-RC2)
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2013-08-22 00:51:48 UTC (releng/9.1, 9.1-RELEASE-p6)
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2013-08-15 04:35:25 UTC (stable/8, 8.4-STABLE)
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2013-08-22 00:51:56 UTC (releng/8.4, 8.4-RELEASE-p3)
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2013-08-22 00:51:56 UTC (releng/8.3, 8.3-RELEASE-p10)
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CVE Name: CVE-2013-5209
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For general information regarding FreeBSD Security Advisories,
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including descriptions of the fields above, security branches, and the
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following sections, please visit <URL:http://security.FreeBSD.org/>.
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0. Revision History
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v1.0 2013-08-22 Initial release.
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v1.1 2013-09-07 Binary patch released for 9.2-RC1.
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I. Background
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The SCTP protocol provides reliable, flow-controlled, two-way transmission
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of data. It is a message oriented protocol and can support the SOCK_STREAM
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and SOCK_SEQPACKET abstractions.
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The SCTP protocol checks the integrity of messages by validating the state
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cookie information that is returned from the peer.
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II. Problem Description
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When initializing the SCTP state cookie being sent in INIT-ACK chunks,
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a buffer allocated from the kernel stack is not completely initialized.
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III. Impact
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Fragments of kernel memory may be included in SCTP packets and
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transmitted over the network. For each SCTP session, there are two
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separate instances in which a 4-byte fragment may be transmitted.
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This memory might contain sensitive information, such as portions of the
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file cache or terminal buffers. This information might be directly
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useful, or it might be leveraged to obtain elevated privileges in
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some way. For example, a terminal buffer might include a user-entered
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password.
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IV. Workaround
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No workaround is available, but systems not using the SCTP protocol
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are not vulnerable.
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V. Solution
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Perform one of the following:
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1) Upgrade your vulnerable system to a supported FreeBSD stable or
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release / security branch (releng) dated after the correction date.
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2) To update your vulnerable system via a source code patch:
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The following patches have been verified to apply to the applicable
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FreeBSD release branches.
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a) Download the relevant patch from the location below, and verify the
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detached PGP signature using your PGP utility.
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# fetch http://security.FreeBSD.org/patches/SA-13:10/sctp.patch
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# fetch http://security.FreeBSD.org/patches/SA-13:10/sctp.patch.asc
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# gpg --verify sctp.patch.asc
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b) Apply the patch.
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# cd /usr/src
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# patch < /path/to/patch
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c) Recompile your kernel as described in
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<URL:http://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the
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system.
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3) To update your vulnerable system via a binary patch:
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Systems running a RELEASE version of FreeBSD on the i386 or amd64
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platforms can be updated via the freebsd-update(8) utility:
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# freebsd-update fetch
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# freebsd-update install
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VI. Correction details
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The following list contains the correction revision numbers for each
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affected branch.
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Branch/path Revision
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- -------------------------------------------------------------------------
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stable/8/ r254354
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releng/8.3/ r254632
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releng/8.4/ r254632
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stable/9/ r254352
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releng/9.1/ r254631
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releng/9.2/ r254355
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- -------------------------------------------------------------------------
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To see which files were modified by a particular revision, run the
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following command, replacing NNNNNN with the revision number, on a
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machine with Subversion installed:
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# svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base
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Or visit the following URL, replacing NNNNNN with the revision number:
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<URL:http://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>
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VII. References
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<other info on vulnerability>
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<URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-5209>
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The latest revision of this advisory is available at
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<URL:http://security.FreeBSD.org/advisories/FreeBSD-SA-13:10.sctp.asc>
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