The “pidfile” or “driftfile” directives in NTP ntpd 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77, when ntpd is configured to allow remote configuration, allows remote attackers with an IP address that is allowed to send configuration requests, and with knowledge of the remote configuration password to write to arbitrary files via the :config command.
rhn.redhat.com/errata/RHSA-2016-0780.html
rhn.redhat.com/errata/RHSA-2016-2583.html
support.ntp.org/bin/view/Main/NtpBug2902
www.debian.org/security/2015/dsa-3388
www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
www.securityfocus.com/bid/77278
www.securitytracker.com/id/1033951
bugzilla.redhat.com/show_bug.cgi?id=1254547
security.gentoo.org/glsa/201607-15
security.netapp.com/advisory/ntap-20171004-0001/