Cloudflare blocks the largest DDoS attack in internet history
Nearly 38TB of malicious traffic hit a hosting provider in under a minute, with Cloudflare’s defences redirecting and filtering the attack efficiently.
Cloudflare has blocked what it describes as the largest distributed denial-of-service (DDoS) attack ever recorded after nearly 38 terabytes of data were unleashed in just 45 seconds.
The onslaught generated a peak traffic rate of 7.3 terabits per second and targeted nearly 22,000 destination ports on a single IP address managed by an undisclosed hosting provider.
Instead of relying on a mix of tactics, the attackers primarily used UDP packet floods, which accounted for almost all attacks. A small fraction employed outdated diagnostic tools and methods such as reflection and amplification to intensify the network overload.
These techniques exploit how some systems automatically respond to ping requests, causing massive data feedback loops when scaled.
Originating from 161 countries, the attack saw nearly half its traffic come from IPs in Brazil and Vietnam, with the remainder traced to Taiwan, China, Indonesia, and the US.
Despite appearing globally orchestrated, most traffic came from compromised devices—often everyday items infected with malware and turned into bots without their owners’ knowledge.
To manage the unprecedented data surge, Cloudflare used a decentralised approach. Traffic was rerouted to data centres close to its origin, while advanced detection systems identified and blocked harmful packets without disturbing legitimate data flows.
The incident highlights the scale of modern cyberattacks and the growing sophistication of defences needed to stop them.
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