Cloudflare Fends Off History’s Largest DDoS Attack

Cloudflare has blocked a widescale DDoS attack at 3.8 Tbps, the largest ever recorded.

By Marco Rizal - Editor, Journalist 4 Min Read
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Cloudflare has blocked a widescale DDoS attack at 3.8 Tbps, the largest ever recorded.

  • The attack spanned over a month, targeting customers in telecom and finance sectors.
  • Previous major attacks by Google and AWS fall short of Cloudflare’s latest battle.
  • Cloudflare mitigated a record 3.8 Tbps DDoS attack, the largest publicly disclosed.

A massive Distributed Denial of Service (DDoS) attack, peaking at 3.8 terabits per second (Tbps), struck Cloudflare's network, nearly causing one of the internet's biggest disruptions in history.

According to Cloudflare, they described it as the largest ever recorded, surpassing the previous record set by Microsoft's 3.47 Tbps DDoS attack in November 2021. Cloudflare, on the other hand, treated it like any other day at work.

Cloudflare's defenses automatically mitigated the attack, along with over 100 other hyper-volumetric Layer 3/4 DDoS attacks in September.

Many of these attacks exceeded 2 billion packets per second (Bpps) and pushed 3 Tbps, a size that would have likely crippled most businesses unprepared to handle such traffic volumes.

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Credit: Cloudflare

The 3.8 Tbps attack dwarfs previous DDoS attempts, including the 71 million request-per-second DDoS attack Cloudflare received in February 2023 from a botnet using virtual machines.

This was previously the largest known attack in terms of requests per second (rps), but it has since been surpassed by this latest strike.

A similar magnitude was observed in the July 2023 DDoS attack, which was primarily powered by a VM-based botnet.

Meanwhile, Google reported a massive 398 million rps DDoS in October 2023, marking yet another high point in the ongoing conflict between cyber attackers and cloud infrastructure providers.

The growing size of these attacks demonstrates how dangerous modern botnets can be, with hacked web servers, home routers, and even DVRs weaponized into massive botnets.

This DDoS attack is particularly terrifying due to its sheer size. At 3.8 Tbps, the attack had the potential to overwhelm the bandwidth capacity of any internet provider that did not have a globally distributed network like Cloudflare.

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Credit: Cloudflare

The attack primarily targeted customers in the financial services, internet, and telecommunications industries, relying heavily on UDP flood attacks.

According to Cloudflare, the botnet's backbone was made up of compromised devices from Vietnam, Russia, Brazil, Spain, and the United States, as well as ASUS routers with a critical vulnerability, making the attack both geographically distributed and extremely powerful.

They were able to thwart the attack through the use of its robust anycast network, which distributes traffic across multiple servers worldwide.

“The network is built to handle these high-volume attacks,” Cloudflare's security team explained.

Their global coverage, combined with autonomous systems that analyze incoming traffic and filter malicious data in real time, enabled them to handle massive traffic volumes while maintaining customer service to assure customers that everything is fine.

Cloudflare is one of the world's largest and most widely used web infrastructure and security companies, providing a critical backbone for millions of websites around the world.

Its services include content delivery networks (CDNs) and DDoS protection, ensuring that websites load quickly and remain online even in the face of malicious traffic.

Cloudflare currently serves 24,030,148 websites as of time of writing, including major businesses, news outlets, e-commerce platforms, and financial institutions, and plays an important role in keeping the internet running smoothly.

If Cloudflare fails to withstand such a massive attack, the consequences could be disastrous, resulting in outages across vast swathes of the internet.

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