On Tuesday, September 20th around 8:00PM, KrebsOnSecurity.com was the target of a record-breaking 620Gbps volumetric DDoS attack designed to take the site offline. A few days later, the same type of botnet was used in a 1Tbps attack targeting the French webhoster OVH. What’s interesting about these attacks was that compared to previous record-holding attacks, which were less than half the traffic volume, they were not using amplification or reflection. In the case of KrebsOnSecurity, the biggest chunk of the attack traffic came in the form of GRE, which is very unusual. In the OVH attack, more than 140,000 unique IPs were reported in what seemed to be a SYN and ACK flood attack.