This Friday on the east coast, major sites’ service was interrupted by a massive cyber attack. The affected sites include Amazon, PayPal, Twitter, Netflix, Spotify and Reddit. Some of the websites were shut down for up to two hours. The attack was performed using a method called DDoS (Distributed Denial of Service), which aims to flood the sites’ bandwidth with too much traffic.

Internet services company Dyn said that they had managed to thwart  the attack only two hours after it began. However, later in the day they reported they were fighting “several” attacks.

Dyn told CNBC the attacks are “well planned and executed, coming from tens of millions of IP addresses at the same time.”

“Our engineers continue to investigate and mitigate several attacks aimed against the Dyn Managed DNS infrastructure,” the company wrote on their website. Attacks continued as the day went on.

Dyn reported the attacks were coming not only from computers but from DVRs, printers and other appliances connected to the internet. The devices are thought to be infected by malware released on the web in recent weeks.

It is still not known who was behind the attack. The Department of Homeland Security reported that it is “looking into all potential causes” of the attack. One U.S. intelligence official said North Korea had been ruled out as a suspect.

“DDoS” became the top trending topic on Twitter, and a lot of companies informed their users that they are experiencing technical difficulties.

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