A major cyberattack shut down or slowed dozens of popular websites Friday, and the cause was still being investigated into the evening.

  • Twitter, Netflix, Reddit among sites affected
  • Dyn calls what happened a cyberattack
  • Cybersecurity expert says it may be extortion

Internet infrastructure provider Dyn said it resolved one attack but disclosed subsequent attacks hours later that were causing more disruptions, according to Reuters. Among the sites affected was the PlayStation Network.

The company said it was a "DDoS" attack, which means "distributed denial of service." That's when a website is flooded with so much traffic that it clogs and interrupts normal service.

For about two hours Friday morning, major websites such as Twitter, Netfilx, Spotify, Airbnb, Etsy, Reddit and others went down for many people in the United States. Some outages were still being reported Friday afternoon.

Dyn is calling what happened a cyberattack, but it doesn't know who is responsible.

A government official said the U.S. is "looking at all possible scenarios," including possible cyber activity.

Cybersecurity expert Stu Sjouwerman, the CEO of KnowBe4, a cybersecurity training company, speculated a calculated attack.

"What this likely is, is there is a massive amount of extortion going on at the moment, where bad guys say to a company like Dyn, 'Pay us or we shut you down,' " Sjouwerman said.

"And it may very well be that Dyn refused to pay, and then you get a big attack like this to show the company that refused to pay that they can be shut down so they will pay next time."

Sjourwerman said the situation could get worse before it gets better, because the perpetrators are getting access to more and more.

Many of the affected companies started tweeting that they were experiencing problems at about 7 a.m., and most started reporting normalcy a couple of hours later. However, sites went down at least two more times during the day.

Dyn's status page said the DDoS attacks mostly affected users along the East Coast. It's unclear whether any account information was stolen.

WikiLeaks connection?

Document leaks group WikiLeaks insinuated on Twitter that supporters of the group may have been behind Friday's DDOS attacks.

The second tweet was in reference to the Ecuadorian Embassy in London, where founder Julian Assange lives, cutting his access to the Internet earlier this week.

The Ecuador government acknowledged cutting and limiting access, saying they did not want to be a party to influencing a foreign government's elections.

WikiLeaks is currently releasing daily caches of emails tied to the Clinton campaign.