<![endif] CloudFlare Blog home How it works Support Login Sign up Published on February 13, 2014 01:00AM by Matthew Prince . Tweet On Monday we mitigated a large DDoS that targeted one of our customers. The attack peaked just shy of 400Gbps. We've seen a handful of other attacks at this scale, but this is the largest attack we've seen that uses NTP amplification. This style of attacks has grown dramatically over the last six months and poses a significant new threat to the web. Monday's attack serves as a good case study to examine how these attacks work. Before diving into the particular details of this attack, it's important to understand the basic mechanics of how NTP amplification attacks work. This is a quick overview of how these attacks occur. John Graham-Cumming on our team previously wrote a detailed primer on NTP amplification attacks if you're int...