Cloudflare reveals the largest DDoS attack in history

Cloudflare has announced the successful defense of its largest DDoS attack to date. During the incident, one of the company’s customers was attacked with a peak traffic volume of 7.3 Tbps, equivalent to 37.4 TB of data transferred in 45 seconds.

The main attack vector was based on UDP flooding, a type of traffic that does not require confirmation of delivery and is often used in online games and streaming video. Due to its structure, the UDP protocol is widely used in DDoS attacks, as it allows you to quickly overload systems.

In addition to UDP flooding, attackers used reflection/amplification attacks, changing the victim’s IP address and forcing third-party services to send traffic back to it, increasing the load.

According to Cloudflare, in 45 seconds, as much data as is contained in approximately 9,350 HD movies or 12.5 million photos was transferred. This is not the first case of record-breaking DDoS attacks in recent years. In January 2022, Microsoft recorded an attack with a capacity of 3.47 Tbps, in October 2024 – 5.6 Tbps, and in April 2025 – 6.5 Tbps. The current case has become a new anti-record.

The attacks traditionally use botnets – networks of infected devices, including household appliances and IoT gadgets. Such attacks are relatively inexpensive and are often used to disrupt services or for the purpose of extortion.