223eda903e
Fix Denial of Service vulnerability in named(8). [13:07] Fix a bug that allows remote client bypass the normal access checks when when -network or -host restrictions are used at the same time with -mapall. [13:08]
120 lines
4.3 KiB
Text
120 lines
4.3 KiB
Text
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=============================================================================
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FreeBSD-SA-13:08.nfsserver Security Advisory
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The FreeBSD Project
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Topic: Incorrect privilege validation in the NFS server
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Category: core
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Module: nfsserver
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Announced: 2013-07-26
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Credits: Rick Macklem, Christopher Key, Tim Zingelman
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Affects: FreeBSD 8.3, FreeBSD 9.0 and FreeBSD 9.1
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Corrected: 2012-12-28 14:06:49 UTC (stable/9, 9.2-BETA2)
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2013-07-26 22:40:23 UTC (releng/9.1, 9.1-RELEASE-p5)
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2013-01-06 01:11:45 UTC (stable/8, 8.3-STABLE)
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2013-07-26 22:40:29 UTC (releng/8.3, 8.3-RELEASE-p9)
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CVE Name: CVE-2013-4851
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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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I. Background
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The Network File System (NFS) allows a host to export some or all of its
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file systems so that other hosts can access them over the network and mount
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them as if they were on local disks. FreeBSD includes both server and client
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implementations of NFS.
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II. Problem Description
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The kernel incorrectly uses client supplied credentials instead of the one
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configured in exports(5) when filling out the anonymous credential for a
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NFS export, when -network or -host restrictions are used at the same time.
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III. Impact
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The remote client may supply privileged credentials (e.g. the root user)
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when accessing a file under the NFS share, which will bypass the normal
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access checks.
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IV. Workaround
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Systems that do not provide the NFS service are not vulnerable. Systems that
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do provide the NFS service are only vulnerable when -mapall or -maproot is
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used in combination with network and/or host restrictions.
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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-13:08/nfsserver.patch
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# fetch http://security.FreeBSD.org/patches/SA-13:08/nfsserver.patch.asc
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# gpg --verify nfsserver.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/ r245086
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releng/8.3/ r253694
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stable/9/ r244772
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releng/9.1/ r253693
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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 XXXXXX with the revision number, on a
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machine with Subversion installed:
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# svn diff -cXXXXXX --summarize svn://svn.freebsd.org/base
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Or visit the following URL, replacing XXXXXX with the revision number:
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<URL:http://svnweb.freebsd.org/base?view=revision&revision=XXXXXX>
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VII. References
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<URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-4851>
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The latest revision of this advisory is available at
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http://security.FreeBSD.org/advisories/FreeBSD-SA-13:08.nfsserver.asc
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