NTP before 4.2.8p10 and 4.3.x before 4.3.94, when using PPSAPI, allows local users to gain privileges via a DLL in the PPSAPI_DLLS environment variable.
https://support.apple.com/HT208144
http://www.securitytracker.com/id/1039427
http://www.securitytracker.com/id/1038123
http://www.securityfocus.com/bid/97074
http://support.ntp.org/bin/view/Main/SecurityNotice#March_2017_ntp_4_2_8p10_NTP_Secu