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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2017.0947 Multiple vulnerabilities of ntp 13 April 2017 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: ntp Publisher: FreeBSD Operating System: FreeBSD Impact/Access: Execute Arbitrary Code/Commands -- Existing Account Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2017-6464 CVE-2017-6463 CVE-2017-6462 CVE-2016-9042 Original Bulletin: https://security.freebsd.org/advisories/FreeBSD-SA-17:03.ntp.asc - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-17:03.ntp Security Advisory The FreeBSD Project Topic: Multiple vulnerabilities of ntp Category: contrib Module: ntp Announced: 2017-04-12 Credits: Network Time Foundation Affects: All supported versions of FreeBSD. Corrected: 2017-03-28 04:48:17 UTC (stable/11, 11.0-STABLE) 2017-04-12 06:24:35 UTC (releng/11.0, 11.0-RELEASE-p9) 2017-03-28 04:48:55 UTC (stable/10, 10.3-STABLE) 2017-04-12 06:24:35 UTC (releng/10.3, 10.3-RELEASE-p18) CVE Name: CVE-2017-6464, CVE-2017-6462, CVE-2017-6463, CVE-2016-9042 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.FreeBSD.org/>. I. Background The ntpd(8) daemon is an implementation of the Network Time Protocol (NTP) used to synchronize the time of a computer system to a reference time source. II. Problem Description A vulnerability was discovered in the NTP server's parsing of configuration directives. [CVE-2017-6464] A vulnerability was found in NTP, in the parsing of packets from the DPTS Clock. [CVE-2017-6462] A vulnerability was discovered in the NTP server's parsing of configuration directives. [CVE-2017-6463] A vulnerability was found in NTP, affecting the origin timestamp check function. [CVE-2016-9042] III. Impact A remote, authenticated attacker could cause ntpd to crash by sending a crafted message. [CVE-2017-6463, CVE-2017-6464] A malicious device could send crafted messages, causing ntpd to crash. [CVE-2017-6462] An attacker able to spoof messages from all of the configured peers could send crafted packets to ntpd, causing later replies from those peers to be discarded, resulting in denial of service. [CVE-2016-9042] IV. Workaround No workaround is available, but systems not running ntpd(8) are not affected. Network administrators are advised to implement BCP-38, which helps to reduce the risk associated with these attacks. 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. The ntpd service has to be restarted after the update. A reboot is recommended but not 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 The ntpd service has to be restarted after the update. A reboot is recommended but not 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. [FreeBSD 11.0] # fetch https://security.FreeBSD.org/patches/SA-17:03/ntp-11.0.patch.xz # fetch https://security.FreeBSD.org/patches/SA-17:03/ntp-11.0.patch.xz.asc # gpg --verify ntp-11.0.patch.xz.asc [FreeBSD 10.3] # fetch https://security.FreeBSD.org/patches/SA-17:03/ntp-10.3.patch.xz # fetch https://security.FreeBSD.org/patches/SA-17:03/ntp-10.3.patch.xz.asc # gpg --verify ntp-10.3.patch.xz.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile the operating system using buildworld and installworld as described in <URL:https://www.FreeBSD.org/handbook/makeworld.html>. Restart the applicable daemons, or reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - - ------------------------------------------------------------------------- stable/10/ r316069 releng/10.3/ r316722 stable/11/ r316068 releng/11.0/ r316722 - - ------------------------------------------------------------------------- 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: <URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-9042> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-6462> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-6463> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-6464> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-17:03.ntp.asc> - -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.1.19 (FreeBSD) iQIzBAEBCgAdFiEEHPf/b631yp++G4yy7Wfs1l3PaucFAljty+gACgkQ7Wfs1l3P audFpxAA30Po/44RV8x98fcopL+/qX0bKhs2yORCcYs/ebrPaDW6ghdqPAPyNDen qJSoEU6FFZxU508reu6mcJIze0YzSC2D4Xe+BjtVjTUhgZ1mUlfx+0Dqa6DsmyPE wreYZ0+aPJPSg82P4pOR+Oo4Omh0BHXw/Yu+uJxd+VSGAWg9zJk9QcRyy3QKsPFn YbMYjAsMk1x2i/q6GzRnoJXAFT9c1QsKRP1QU3JivDEQEYwreqKxkG7Ex9OkUOmL CIPVG19K7iddnMfiQPjhPhyAOFWrtKMm1rjcg1vSEMUQ24MtVotGOgNkKXEf0vjT eVX91sIRYGgy9utg6Mg4pnDT7m94PMh7mORgfphHg7l7LFVGYKAbHF7khIMtrs4k /ZU5i7xZqKR6xNm4oWtaBC9EipkWfjnXjBRG30t3kdD2r7ElJ+Y3mvPdalFsxd+U gP2Wgn//byToXVUGFLChR7KSWDOjUpdiGu3UUDG4LmG/U4whDsSobPgOF3SzbALF mx8f7OWkOYCnQ9WuhI3PVvCdLncjZ5UdLaQ5nP53pn3rGk9C4MJpGlTI2iS1gwFV n09mE5zXueI3jVJm+An2X2Z3C8fTCRHb7n3Sej2wnrgiXk8z/8ftX6VJcUxdgW+A OYFztl0iKgjgEXix33FZ5baivohQVhAT5rUQRQ/+gcrvL8rbJQg= =58Te - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. 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It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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