Microsoft mitigated the largest cloud DDoS ever recorded, 15.7 Tbps

Microsoft says the Aisuru botnet launched a 15.7 Tbps DDoS on Azure from 500k IPs, using massive UDP floods peaking at 3.6 B pps. On October 24, 2025, Azure DDoS Protection detected and mitigated a massive multi-vector attack that peaked at 15.72 Tbps and 3.64 billion pps, the largest cloud DDoS ever observed, aimed at a single Australian endpoint.

Azure’s global protection network filtered the traffic, keeping services online, and the attack originated from the Aisuru botnet, a Turbo Mirai-class IoT botnet using compromised home routers and cameras. The report notes the attack used vast UDP floods from more than 500,000 IPs with little spoofing and random source ports, making traceback easier. It highlights how attackers are scaling with faster fibre-to-the-home speeds and more powerful IoT devices, pushing DDoS sizes higher.