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CinchOps Cyber Alert: Record-Breaking 11.5 Tbps DDoS Attack Shakes the Internet

The Internet’s Largest DDoS Attack Just Happened – Comprehensive Network Protection Against Evolving Attacks

Cyber Alert
The Largest DDoS Attack Ever Recorded Lasted 35 Seconds. It Peaked at 11.5 Terabits Per Second.

Cloudflare blocked it without a hiccup - but the record has now tripled in under a year. Here is what that means for your business.

TL;DR
Over Labor Day weekend 2025, Cloudflare mitigated the largest distributed denial-of-service (DDoS) attack on record - a hyper-volumetric UDP flood that peaked at 11.5 terabits per second and lasted about 35 seconds. It came from a mix of compromised Internet-of-Things devices and cloud providers, and Cloudflare stopped it with automatic rate-limiting and IP filtering, so customers saw no disruption. The record keeps falling fast: 3.8 Tbps in October 2024, 7.3 Tbps in June 2025, now 11.5 Tbps - a near-tripling in under a year. Cloudflare also blocked 27.8 million DDoS attacks in the first half of 2025 alone, more than all of 2024. Your business almost certainly cannot absorb an attack like this on its own hardware, which is exactly why cloud-based DDoS protection has become a baseline, not a luxury.

A single DDoS attack hit 11.5 terabits per second - the largest ever recorded - and the previous record had stood for only about three months.

DDoS attacks flood a target with so much junk traffic that legitimate users cannot get through. What makes this record notable is not just its size but its pace: the ceiling keeps rising, and it is rising fast. For a small or midsize business, the takeaway is not panic - it is that defending against this scale of attack is no longer something you can do alone on your own equipment.

The good news: Cloudflare stopped an 11.5 Tbps flood automatically, in seconds, with no customer disruption. Scale like that is exactly what cloud DDoS protection is built to absorb.

What Happened

A record-breaking flood, blocked before anyone noticed.

Cloudflare mitigated an 11.5 Tbps UDP flood in about 35 seconds - and the DDoS record has now tripled in under a year.

The attack was a UDP flood: attackers sent a massive volume of UDP packets, with spoofed source addresses, at the target to exhaust its capacity. It originated from a combination of IoT devices and cloud providers - Cloudflare initially attributed much of it to one cloud source, then corrected that no single provider was the majority. What stands out is how quickly the records are falling.

WhenPeak volumeNote
October 20243.8 Tbpsa record at the time
June 20257.3 Tbpsroughly doubled in months
September 202511.5 Tbpslargest ever recorded
DDoS ATTACKS CLOUDFLARE MITIGATED All of 2024 21.3M First half of 2025 27.8M
Half of 2025 already exceeded all of 2024. Source: Cloudflare.

How These Attacks Work

Cheap, hijacked devices add up to unstoppable-looking volume.

Botnets of compromised IoT devices and cloud instances let attackers generate more traffic than most networks could ever absorb.

  • Volume is the weapon. A UDP flood does not exploit a clever bug - it simply sends more traffic than the target can handle, so raw capacity decides who wins.
  • IoT devices are the ammunition. Poorly secured cameras, recorders, and routers get conscripted into botnets that each add a trickle - and millions of trickles become a torrent.
  • Cloud adds firepower. Attackers increasingly abuse cloud infrastructure to boost bandwidth, blending it with IoT traffic to reach terabit scale.
  • The volume is climbing. Cloudflare blocked 27.8 million DDoS attacks in the first half of 2025 - already more than the 21.3 million it saw in all of 2024.

Because these attacks are about sheer size, the only reliable defense is a network large enough to soak them up. That is a scale no single business runs on its own.

How to Protect Your Business

You will not out-buy a botnet - so you route around it.

Cloud-based DDoS protection, monitoring, and redundancy keep you online even when the traffic is measured in terabits.

  • Use cloud-based DDoS protection. A provider with global capacity absorbs volumetric floods before they reach your servers - the only approach that scales to terabit attacks.
  • Monitor your traffic. Detection that flags unusual traffic early buys time to respond before an attack overwhelms you.
  • Build in redundancy. Failover infrastructure and multiple paths keep services available if one route is saturated.
  • Filter and rate-limit. Firewall rules and rate limiting cut down the malicious traffic that does get through.
  • Have a DDoS response plan. A tested plan - who to call, what to switch on - turns an attack into a managed event, not a scramble.

The scale of modern DDoS means on-premises hardware alone cannot keep up. Cloud protection with a large global network has become the baseline for staying online.

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Eleven and a half terabits in thirty-five seconds is a number most business owners cannot picture - and that is the point. You are never going to buy enough bandwidth to fight that on your own. The move is to sit behind a network that already has it. Defense at that scale is a service, not a server.
Shane Stevens, CEO, CinchOps - LinkedIn

Stay Online Through Any Flood

CinchOps sets up and manages cloud-based DDoS protection, traffic monitoring, and failover so a record-breaking attack never takes your business offline - as part of our cybersecurity and managed IT services.

Explore CinchOps cybersecurity →

How CinchOps Helps Secure Your Business

CinchOps is a Katy, Texas managed IT services provider serving businesses across the Houston metro, keeping you online against attacks of any size.

  • Cloud DDoS mitigation. Provider-scale protection that absorbs volumetric floods before they reach you.
  • 24/7 network monitoring. Early detection of unusual traffic and automatic response.
  • Redundancy and failover. Infrastructure designed to keep services running under attack.
  • Firewall and traffic filtering. Rules and rate limiting that cut malicious traffic.
  • Incident response and continuity. Tested plans that keep your business operating during an attack.

Do not wait for a flood to test your defenses. Contact CinchOps to build DDoS resilience for your business.

Frequently Asked Questions

What was the 11.5 Tbps DDoS attack?

In early September 2025, Cloudflare mitigated the largest DDoS attack on record - a hyper-volumetric UDP flood that peaked at 11.5 terabits per second and lasted about 35 seconds. It came from a mix of compromised IoT devices and cloud providers and was blocked automatically, with no customer disruption.

Is this the largest DDoS attack ever?

Yes, at the time it was recorded. It broke the previous record of 7.3 Tbps set in June 2025, which had itself topped a 3.8 Tbps record from October 2024 - the ceiling roughly tripled in under a year.

What is a UDP flood?

A UDP flood is a volumetric DDoS attack that overwhelms a target with UDP packets, often using spoofed source addresses. The target burns resources checking and responding to each packet, which exhausts its capacity and blocks legitimate traffic.

Can a small business defend against attacks this large?

Not with on-premises hardware alone - no single business has terabits of spare capacity. The practical defense is cloud-based DDoS protection from a provider with a large global network that can absorb the flood before it reaches your servers.

Are DDoS attacks becoming more common?

Yes. Cloudflare blocked 27.8 million DDoS attacks in the first half of 2025 alone - already more than the 21.3 million it mitigated across all of 2024 - so both the size and the frequency are rising.

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