25bn botnet attacks thwarted, says cyber watchdog

A cybersecurity company says it thwarted a record-breaking distributed denial of service (DDos) attack, fending off a staggering 25.3 billion server requests in the space of four hours.

And contrary to what some might think, the intended target of the barrage was no Western concern, but an unnamed Chinese telecoms company that cyber-guardian Imperva says is frequently singled out for such attacks.

“While attacks with over one million requests per second (RPS) aren’t new, we’ve previously only seen them last for several seconds to a few minutes,” said Imperva, adding that this four-hour assault peaked at 3.9 million RPS.

The scale of the onslaught points to the growing efficacy of bad actors in the cyber field, but also shines a ray of light in that – for now at least – their infosecurity antagonists seem equal to the task of opposing them.

The attack, only disclosed by Impervia this week, took place on June 27, and employed a technique known as multiplexing – sending multiple packets, themselves each containing multiple server requests, via individual connections with the aim of shutting them down due to overload.

“This technique can bring servers down using a limited number of resources, and such attacks are extremely difficult to detect,” said Imperva.

Most DDos attacks handled by the cybersecurity firm last less than fifteen minutes, with just roughly one in ten lasting an hour or more.

The threat actors had to marshal an army of hijacked ‘zombie’ machines of apocalyptic proportions to carry out the attack, constructing a giant botnet of 170,000 internet protocol addresses across 180 countries, most of them based in the US, Indonesia, and Brazil.

“Some of these servers are hosted on various public clouds, and even cloud security service providers,” said Imperva.