A massive distributed-denial-of-service (DDoS) attack ever, reaching over 400Gbps, has hit the content delivery network and security provider CloudFlare, by exploiting a key weakness in the internet infrastructure.

Hackers leveraged vulnerability in the Network Time Protocol (NTP), which allows flooding servers with massive data by synchronising computer clocks.

Cloudflare CEO Matthew Price tweeted: "Very big NTP reflection attack hitting us right now."

"Appears to be bigger than the #Spamhaus attack from last year. Mitigating," Price added.

"Someone’s got a big, new cannon. Start of ugly things to come."

Without disclosing the customer targeted by the attack, the security firm noted that the attack was directed at its servers in Europe and added that ‘these NTP reflection attacks are getting really nasty.’

The latest DDoS attack is 100Gbps massive than last year’s attack on anti-spam service Spamhaus CloudFlare, and major Internet switching stations in Amsterdam, Frankfurt, and London.