Record 29.7 Tbps DDoS Attack Linked to AISURU Botnet with up to 4 Million Infected Hosts

Cloudflare has disclosed that it detected and mitigated the largest ever distributed denial-of-service (DDoS) attack, hitting 29.7 terabits per second (Tbps). The assault originated from a DDoS botnet-for-hire called AISURU, which has been linked to hyper-volumetric attacks and is believed to be powered by a network of 1–4 million infected hosts worldwide.

The 69-second UDP carpet-bombing campaign targeted an average of 15,000 destination ports per second and used randomised packet attributes to evade defenses; Cloudflare also noted a separate 14.1 Bpps DDoS attack from the same botnet in the same period.

The AISURU botnet has prominently attacked telecommunications providers, gaming companies, hosting providers and financial services, with Cloudflare reporting a total of 2,867 AISURU attacks mitigated since the start of the year and 8.3 million DDoS attacks blocked overall in the period. Cloudflare said the number of DDoS attacks above 1 Tbps and other trends point to increasing sophistication and volume in 2025.

The article adds that 36.2 million DDoS attacks were thwarted in 2025, including 1,304 network-layer attacks exceeding 1 Tbps, reflecting a broader shift in threat activity.