Cloudflare blocks the largest DDoS attack of all time

Cloudflare recently fended off the largest DDoS attack of all time. The global attack via compromised network devices lasted a month and peaked at a whopping 3.8 terabits per second (Tbps) of data transferred.

Cloudflare automatically blocked the largest DDoS attack of all time in September of this year. This was a DDoS attack that targeted the L3/L4 network layers of the affected companies.

For a month, these specific network layers were bombarded with more than 100 so-called “hypervolumetric” DDoS attacks to flood the targets’ network infrastructure with junk data.

A volumetric DDoS attack bombards the target with data until bandwidth is saturated or the processing capabilities of network devices or applications are exhausted. This results in legitimate users being denied access to the networks or devices/applications.

Peak value of 3.8 Tbit/s

These recent attacks often peaked at more than 2 billion packets (2 bpps) and 3 terabits (Tbps) per second, according to Cloudflare. The highest peak ever recorded for this attack even reached 3.8 Tbit/s.

The targets of the attacks included companies in the financial services, telecommunications and internet services industries.

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Source of attack

The source of the attacks was global, but came mainly from countries such as Russia, Vietnam, the United States, Brazil and Spain. The hackers who launched the attack used compromised network devices, including Mikrotik systems, DVRs and web servers.

Compromised Asus routers in particular were a popular tool in this attack. This is because these routers were vulnerable to exploiting the critical CVE-2024-3080 vulnerability discovered earlier this year.

Additionally, this large-scale attack exploited the User Datagram Protocol (UDP) on a fixed port. This protocol enables fast data transfer but does not require a formal connection setup, points out Cloudflare.

Read also: DDoS attacks are becoming increasingly complex and frequent