Network Time Protocol, or NTP, syncs time between machines on the network, and runs over port 123 UDP. Researchers spotted a spike in so-called NTP reflection attacks this month. Attackers appear to be employing NTP for DDoS for DDoSing similar to the way DNS is being abused in such attacks. NTP is one of those set-it-and-forget-it protocols that is configured once and often is not updated, says Symantec.”]
Source: https://www.darkreading.com/attacks-breaches/attackers-wage-network-time-protocol-based-ddos-attacks