Cloudflare Blocks Record 11.5 Tbps DDoS Attack
Cloudflare has shattered its own record by blocking an unprecedented 11.5 Tbps DDoS attack, the largest ever witnessed. The assault, lasting just 35 seconds, was a UDP flood mainly originating from Google Cloud and part of weeks-long waves targeting a single IP.
The 11.5 Tbps attack, which occurred in early October 2025, was a staggering 12% greater than the previous peak and 1 Tbps more than a previous attack reported by Brian Krebs. It targeted a single IP, blasting an average of 21,925 ports per second and peaking at a staggering 34,517. In just 35 seconds, it hurled 37.4 TB of data, equivalent to streaming 9,350 HD movies or downloading 9.35 million songs in under a minute.
Cloudflare's systems automatically blocked this record-breaking attack, as they have done with hundreds of massive DDoS attacks in recent weeks. The company previously blocked a 7.3 Tbps attack in June 2025, which was multivector, with 99.996% as UDP floods, and included other types like QOTD, Echo, NTP, Mirai, Portmap, and RIPv1. This attack was 12% greater than the previous peak and 1 Tbps more than a previous attack reported by Brian Krebs.
The 11.5 Tbps DDoS attack blocked by Cloudflare in early October 2025 underscores the escalating threat landscape. With attacks growing in size and frequency, robust and automated protection systems like Cloudflare's are crucial for safeguarding against these record-breaking assaults.
