Ars Technica just put up a piece on the effects of various attacks on NTP with a link to the original paper. http://arstechnica.com/security/2015/10/new-attacks-on-network-time-protocol-can-defeat-https-and-create-chaos/ Also, I was looking at my firewall last week and it showed over 10,000 attempts to hack NTPD over a period of a couple of days. I usually only see a couple of dozen... somethings afoot out there.