Google Cloud has revealed it blocked the largest distributed denial-of-service (DDoS) attack on record, which peaked at 46 million requests per second (rps). 

The June 1 attack targeted one Google Cloud customer using the Google Cloud Armor DDoS protection service. 

Over the course of 69 minutes beginning at 9:45 am PT, the attackers bombarded its customer's HTTP/S Load Balancer with HTTPS requests, starting at 10,000 rps and within minutes scaling up to 100,000 rps before peaking at a whopping 46 million rps. 

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Google says it is the largest ever attack at Layer 7, referring to the application layer - the top layer - in the OSI model of the Internet. 

The attack on Google's customer was almost twice the size of a HTTPS DDoS attack on a Cloudflare customer in June that peaked at 26 million rps. That attack also relied on a relatively small botnet consisting of 5,067 devices spread over 127 countries.

The attack on Google's customer was also conducted over HTTPS but used "HTTP Pipelining", a technique to scale up rps. Google says the attack came from 5,256 source IP addresses across 132 countries.   

"The attack leveraged encrypted requests (HTTPS) which would have taken added computing resources to generate," Google said.

"Although terminating the encryption was necessary to inspect the traffic and effectively mitigate the attack, the use of HTTP Pipelining required Google to complete relatively few TLS handshakes."

Google says the geographic distribution and types of unsecured services used to generate the attack match the M