A nation state is learning how to take the internet offline

A nation state is learning how to take down the internet, according to IT security expert Bruce Schneier.

Hackers are launching major DDoS attacks on some of the companies who host the web's infrastructure, Schneier warned.

But the length and sophistication of these DDoS attacks are such that it is clear the hackers behind them are trying to learn the limit of the companies' defences.

Schneier said in a blog post: "One week, the attack would start at a particular level of attack and slowly ramp up before stopping. The next week, it would start at that higher point and continue. And so on, along those lines, as if the attacker were looking for the exact point of failure."

The point is not to crash these companies' systems immediately, he added, but to launch attacks on a variety of vectors that require the targets to reveal their entire defence capabilities. The hackers also hit them with probing attacks that manipulate internet addresses, seeing how long it takes for their defences to kick in.

"Someone is extensively testing the core defensive capabilities of the companies that provide critical internet services," Schneier said.

While the hosting providers spoke with Schneier anonymously, he said their findings tally with network security firm Verisign's DDoS trends report, which found attacks became more frequent, persistent and sophisticated in the spring of this year.

Schneier ruled out hacktivists, researchers and cybercriminals, saying the size and scale of the attacks point to a nation state actor, most likely China.

"On the other hand, it's possible to disguise the country of origin for these sorts of attacks," he added.