Crypto-NAK packets in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to bypass authentication.
support.ntp.org/bin/view/Main/NtpBug2941
www.debian.org/security/2015/dsa-3388
www.securityfocus.com/bid/77287
www.securitytracker.com/id/1033951
bugzilla.redhat.com/show_bug.cgi?id=1274265
cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf
h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05270839
security.gentoo.org/glsa/201604-03
security.gentoo.org/glsa/201607-15
security.netapp.com/advisory/ntap-20171004-0001/