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Botnet Generates One of the Largest DDoS Attacks on Record

The attack, which targeted an unnamed financial provider, was mitigated without any human intervention, according to Cloudflare.

 & Michael Kan Principal Reporter

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Last month, someone attempted to launch one of the largest Distributed Denial of Service (DDoS) attacks on record to take down a financial website, according to Cloudflare, an internet infrastructure provider. 

The attack involved generating a flood of internet traffic via HTTP browser-based requests. At its peak, the bombardment reached 17.2 million requests per second. 

“For perspective on how large this attack was: Cloudflare serves over 25 million HTTP requests per second on average,” the company wrote in a blog post on Thursday. “So peaking at 17.2 million rps, this attack reached 68% of our Q2 average rps rate of legitimate HTTP traffic.”

Cloudflare slide

In total, the attack bombarded the company’s servers with 330 million requests in less than one minute. However, Cloudflare says its automated systems were able to automatically detect and mitigate the flood of traffic. 

​​According to Cloudflare, the incident represented the largest application layer-based DDoS attack publicly known. The previous record holder was a 6 million request-per-second attack Google detected last year. 

In 2017, Google also fended off a separate 2.5Tbps DDoS attack believed to be the largest one in history. However, the assault leveraged a different method to bombard the company’s network, so it's measured differently. 

Cloudflare sources the 17.2 million rps attack to a 20,000-machine botnet, which is an army of malware-controlled computers. “Based on the bots’ source IP addresses, almost 15% of the attack originated from Indonesia and another 17% from India and Brazil combined, indicating that there may be many malware infected devices in those countries,” the company says. 

Cloudflare slide showing botnet's makeup by country

The same botnet also launched a separate DDoS attack last week against another Cloudflare customer that reached 8 million rps. But again, the company automatically fended off the attack. As a result, Cloudflare is also spinning the incidents as evidence that its automated DDoS protection services are needed.

About Our Expert

Michael Kan

Michael Kan

Principal Reporter

My Experience

I've been a journalist for over 15 years. I got my start as a schools and cities reporter in Kansas City and joined PCMag in 2017, where I cover satellite internet services, cybersecurity, PC hardware, and more. I'm currently based in San Francisco, but previously spent over five years in China, covering the country's technology sector.

Since 2020, I've covered the launch and explosive growth of SpaceX's Starlink satellite internet service, writing 600+ stories on availability and feature launches, but also the regulatory battles over the expansion of satellite constellations, fights with rival providers like AST SpaceMobile and Amazon, and the effort to expand into satellite-based mobile service. I've combed through FCC filings for the latest news and driven to remote corners of California to test Starlink's cellular service.

I also cover cyber threats, from ransomware gangs to the emergence of AI-based malware. In 2024 and 2025, the FTC forced Avast to pay consumers $16.5 million for secretly harvesting and selling their personal information to third-party clients, as revealed in my joint investigation with Motherboard.

I also cover the PC graphics card market. Pandemic-era shortages led me to camp out in front of a Best Buy to get an RTX 3000. I'm now following how the AI-driven memory shortage is impacting the entire consumer electronics market. I'm always eager to learn more, so please jump in the comments with feedback and send me tips.

The Best Tech I've Had:

  • My first video game console: a Nintendo Famicom
  • I loved my Sega Saturn despite PlayStation's popularity.
  • The iPod Video I received as a gift in college
  • Xbox 360 FTW
  • The Galaxy Nexus was the first smartphone I was proud to own.
  • The PC desktop I built in 2013, which still works to this day.

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