Beat - An Acoustics Inspired DDoS Attack

In November 2020, Cloudflare detected and mitigated a unique ACK DDoS attack called "Beat" that targeted a Magic Transit customer. The attack's packet rate followed a wave-shaped pattern for over 19 hours, resembling an acoustics concept called beat. The attacker launched a flood of packets where the rate was determined by the equation of the beat wave. Cloudflare systems automatically detected and mitigated over 700 DDoS attacks that targeted this customer during the two days of the attack. Flowtrackd, a unidirectional TCP state tracking machine, played a crucial role in detecting and dropping the attack packets at Cloudflare's edge.