dcb9c59cc2
Fix bsnmpd remote denial of service vulnerability. [SA-14:01] Fix ntpd distributed reflection Denial of Service vulnerability. [SA-14:02] Fix OpenSSL multiple vulnerabilities. [SA-14:03] Fix BIND remote denial of service vulnerability. [SA-14:04] Disable hardware RNGs by default. [EN-14:01] Fix incorrect coalescing of stack entry with mmap. [EN-14:02]
167 lines
6.4 KiB
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167 lines
6.4 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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=============================================================================
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FreeBSD-SA-14:02.ntpd Security Advisory
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The FreeBSD Project
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Topic: ntpd distributed reflection Denial of Service vulnerability
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Category: contrib
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Module: ntpd
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Announced: 2014-01-14
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Affects: All supported versions of FreeBSD.
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Corrected: 2014-01-14 19:04:33 UTC (stable/10, 10.0-PRERELEASE)
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2014-01-14 19:12:40 UTC (releng/10.0, 10.0-RELEASE)
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2014-01-14 19:12:40 UTC (releng/10.0, 10.0-RC5-p1)
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2014-01-14 19:12:40 UTC (releng/10.0, 10.0-RC4-p1)
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2014-01-14 19:12:40 UTC (releng/10.0, 10.0-RC3-p1)
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2014-01-14 19:12:40 UTC (releng/10.0, 10.0-RC2-p1)
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2014-01-14 19:12:40 UTC (releng/10.0, 10.0-RC1-p1)
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2014-01-14 19:20:41 UTC (stable/9, 9.2-STABLE)
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2014-01-14 19:42:28 UTC (releng/9.2, 9.2-RELEASE-p3)
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2014-01-14 19:42:28 UTC (releng/9.1, 9.1-RELEASE-p10)
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2014-01-14 19:20:41 UTC (stable/8, 8.4-STABLE)
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2014-01-14 19:42:28 UTC (releng/8.4, 8.4-RELEASE-p7)
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2014-01-14 19:42:28 UTC (releng/8.3, 8.3-RELEASE-p14)
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CVE Name: CVE-2013-5211
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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 ntpd(8) daemon is an implementation of the Network Time Protocol (NTP)
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used to synchronize the time of a computer system to a reference time
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source.
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II. Problem Description
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The ntpd(8) daemon supports a query 'monlist' which provides a history of
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recent NTP clients without any authentication.
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III. Impact
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An attacker can send 'monlist' queries and use that as an amplification of
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a reflection attack.
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IV. Workaround
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The administrator can implement one of the following possible workarounds
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to mitigate the attack:
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1) Restrict access to ntpd(8). This can be done by adding the following
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lines to /etc/ntp.conf:
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restrict -4 default nomodify nopeer noquery notrap
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restrict -6 default nomodify nopeer noquery notrap
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restrict 127.0.0.1
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restrict -6 ::1
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restrict 127.127.1.0
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And restart the ntpd(8) daemon. Time service is not affected and the
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administrator can still perform queries from local host.
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2) Use IP based restrictions in ntpd(8) itself or in IP firewalls to
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restrict which systems can access ntpd(8).
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3) Replace the base system ntpd(8) with net/ntp-devel (version 4.2.7p76 or
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newer)
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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-14:02/ntpd.patch
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# fetch http://security.FreeBSD.org/patches/SA-14:02/ntpd.patch.asc
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# gpg --verify ntpd.patch.asc
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b) Execute the following commands as root:
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# cd /usr/src
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# patch < /path/to/patch
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Recompile the operating system using buildworld and installworld as
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described in <URL:http://www.FreeBSD.org/handbook/makeworld.html>.
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Restart the ntpd(8) daemon, or reboot the 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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Note that the patch would disable monitoring features of ntpd(8) daemon
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by default. If the feature is desirable, the administrator can choose
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to enable it and firewall access to ntpd(8) service.
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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/ r260641
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releng/8.3/ r260647
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releng/8.4/ r260647
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stable/9/ r260641
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releng/9.1/ r260647
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releng/9.2/ r260647
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stable/10/ r260639
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releng/10.0/ r260641
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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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<URL:http://www.symantec.com/connect/blogs/hackers-spend-christmas-break-launching-large-scale-ntp-reflection-attacks>
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<URL:https://cert.litnet.lt/en/docs/ntp-distributed-reflection-dos-attacks>
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<URL:http://bugs.ntp.org/show_bug.cgi?id=1532>
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<URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-5211>
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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-14:02.ntpd.asc>
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