Defending the Internet: how Cloudflare blocked a monumental 7.3 Tbps DDoS attack
10 months ago
- #Cybersecurity
- #Cloudflare
- #DDoS
- Cloudflare blocked the largest DDoS attack ever recorded at 7.3 Tbps in mid-May 2025.
- The attack targeted a hosting provider using Cloudflare's Magic Transit service.
- The attack delivered 37.4 terabytes of data in just 45 seconds, equivalent to streaming 7,480 hours of HD video.
- The attack was a multivector DDoS, with 99.996% being UDP floods and the rest consisting of various reflection attacks.
- Attack originated from over 122,145 source IPs across 5,433 Autonomous Systems in 161 countries, with Brazil and Vietnam contributing nearly half the traffic.
- Cloudflare mitigated the attack using global anycast, autonomous detection, and real-time fingerprinting via eBPF and dosd.
- The company offers a free DDoS Botnet Threat Feed to help service providers identify and mitigate abusive IPs.
- Cloudflare's systems autonomously blocked the attack without human intervention, showcasing their advanced DDoS protection capabilities.