Cyber attacks on a key internet firm have repeatedly disrupted the availability of popular websites across the US.
The White House described the disruption as malicious.
Members of a hacker group claimed responsibility, although their assertion couldn’t be verified.
New Hampshire-based Dyn Inc said its server infrastructure was hit by distributed denial-of-service attacks, which work by overwhelming targeted machines with junk data traffic.
The attack had knock-on effects for users trying to access popular websites from across the US and even in Europe, affecting sites such as Twitter, Netflix and PayPal.
The level of disruption was difficult to gauge, but Dyn provides internet traffic management and optimisation services to some of the biggest names on the web, including Twitter, Netflix and Visa.
Critically, Dyn provides domain name services, which translate the human-readable addresses such as “twitter.com” into an online route for browsers and applications.
Steve Grobman, chief technology officer at Intel Security, compared an outage at a domain name services company to tearing up a map or turning off GPS before driving to the department store.
“It doesn’t matter that the store is fully open or operational if you have no idea how to get there,” he said.
Jason Read, founder of the internet performance monitoring firm CloudHarmony, owned by Gartner Inc, said his company tracked a half-hour-long disruption early on Friday (US time) in which roughly one in two end users would have found it impossible to access various websites from the US east coast.
A second attack later in the day caused disruption to the US east and west coasts as well as impacting some users in Europe.
“It’s been pretty busy for those guys,” Read said. “We’ve been monitoring Dyn for years and this is by far the worst outage event that we’ve observed.”
A full list of affected companies wasn’t immediately available, but Twitter, Netflix, PayPal and the coder hangout Github said they briefly experienced problems earlier on Friday.
New World Hackers claim responsibility
Members of a shadowy hacker collective that calls itself New World Hackers claimed responsibility for the attack via Twitter.
They said they organised networks of connected “zombie” computers that threw a staggering 1.2 terabits per second of data at the Dyn-managed servers.
“We didn’t do this to attract federal agents, only test power,” two collective members who identified themselves as “Prophet” and “Zain” told an AP reporter via Twitter direct message exchange.
The collective, NewWorldHacking on Twitter, has in the past claimed responsibility for similar attacks against sites including ESPNFantasySports.com in September and the BBC on December 31.
The collective has also claimed responsibility for cyber attacks against the Islamic State group.
The two said about 30 people have access to the NewWorldHacking Twitter account. They said 20 are in Russia and 10 in China.
“Prophet” said he is in India. “Zain” said he is in China. The two claimed to be taking “good actions”.