-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-15:07.ntp Security Advisory The FreeBSD Project Topic: Multiple vulnerabilities of ntp Category: contrib Module: ntp Announced: 2015-04-07 Credits: Network Time Foundation Affects: All supported versions of FreeBSD. Corrected: 2015-04-07 20:20:24 UTC (stable/10, 10.1-STABLE) 2015-04-07 20:21:01 UTC (releng/10.1, 10.1-RELEASE-p9) 2015-04-07 20:20:44 UTC (stable/9, 9.3-STABLE) 2015-04-07 20:21:23 UTC (releng/9.3, 9.3-RELEASE-p13) 2015-04-07 20:20:44 UTC (stable/8, 8.4-STABLE) 2015-04-07 20:21:23 UTC (releng/8.4, 8.4-RELEASE-p27) CVE Name: CVE-2014-9297, CVE-2015-1798, CVE-2015-1799 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . 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 The vallen packet value is not validated in several code paths in ntp_crypto.c. [CVE-2014-9297] When ntpd(8) is configured to use a symmetric key to authenticate a remote NTP server/peer, it checks if the NTP message authentication code (MAC) in received packets is valid, but not that there actually is any MAC included, and packets without a MAC are accepted as if they had a valid MAC. [CVE-2015-1798] NTP state variables are updated prior to validating the received packets. [CVE-2015-1799] III. Impact A remote attacker who can send specifically crafted packets may be able to reveal memory contents of ntpd(8) or cause it to crash, when ntpd(8) is configured to use autokey. [CVE-2014-9297] A man-in-the-middle (MITM) attacker can send specially forged packets that would be accepted by the client/peer without having to know the symmetric key. [CVE-2015-1798] An attacker knowing that NTP hosts A and B are peering with each other (symmetric association) can periodically send a specially crafted or replayed packet which will break the synchronization between the two peers due to transmit timestamp mismatch, preventing the two nodes from synchronizing with each other, even when authentication is enabled. [CVE-2015-1799] IV. Workaround No workaround is available, but systems not running ntpd(8) are not affected. 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 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 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. # fetch https://security.FreeBSD.org/patches/SA-15:07/ntp.patch # fetch https://security.FreeBSD.org/patches/SA-15:07/ntp.patch.asc # gpg --verify ntp.patch.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 . 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/8/ r281231 releng/8.4/ r281233 stable/9/ r281231 releng/9.3/ r281233 stable/10/ r281230 releng/10.1/ r281232 - ------------------------------------------------------------------------- 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: VII. References The latest revision of this advisory is available at -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.1.2 (FreeBSD) iQIcBAEBCgAGBQJVJD4CAAoJEO1n7NZdz2rn4doQAKwA67MgX6jiCS4dm1roREi+ G1moTCtqO8LXzH3nOOOk6R/MqFGOs6Jq8D+K/YmdD+4l3c/qCNR0qtv0YcVL0kE+ +xfaIYoGxTzlPjEfpWtceCM0wcAThaF8085hi0IAzG7ozhKPt+Inv33ISgos5c7h zYcbTqBYgQqcJGWdftnYpZ1Nxvoa3wiOlxsOMa4qnNeUakeXcGLZ+1XB5pLjXMZF dHfKhMS6KxcUdHoPgOj468D3bQE05puLk13Kjy+Ti38GhcgMROAsMZVOzgno3J7g D7Hk4dR1dms+6xcSJ0BV4ej0ZfypGv0xiFmUiTk/p7AVbnqrChyjvGca+8reu+Gc Ks/67oZjP5rc0glvRFgjJBmQV/xK2rUK805e4eAm8qBecRjDv6M3mUmPdw5BlgcA 7fcj4VdGkOzLB0Vj7uJFjf3p9cyT+x8yvMtknxehiYmrYnFDsM5d7lcv0+KnRzb2 3bt6maO40wqWIcLErFthcT/nLP+wi35aykNIbGh7PXvqL92gWX+h/xB6YY9Ouo4N hb32W/F5O50MjL6BeY+k5J6usoFrk0EHWK+2Fxm2/AA/5K/JnryWN44F8PVPNzxE f+Vb6CzxBvmflpa/29tF/wSD0oU78AhuShtVrnEVT5ZWJj+/PHBZtcLk2Z+s5hgd hKFvV5Xqix0/U//+yGhj =1fHm -----END PGP SIGNATURE-----