Cyber attacks temporarily shut down Twitter, other US websites

Twitter, PayPal and some other major websites were shut down on the US East Coast for several hours on Friday as an American Internet service provider called Dyn and Amazon's web services unit were hit by waves of cyber attacks, China's Xinhua news agency reports.

Dyn, headquartered in New Hampshire, said in posts on its website that its Domain Name System (DNS) infrastructure suffered a distributed denial-of-service (DDoS) attack starting at 7.10 am (local time).

A DDoS attack is an attempt to make an online service unavailable by overwhelming it with traffic from multiple sources, and the company said the attack is "mainly impacting US East."

About two hours later, Dyn said "services have been restored to normal."

But it wasn't over. The company confirmed that a second DDoS attack took place at 11.52am (local time).

"This DDoS attack may also be impacting Dyn Managed DNS advanced services with possible delays in monitoring," it said.

In an update posted at 5.37 pm (local time), Dyn said its engineers "continue to investigate and mitigate several attacks aimed against the Dyn Managed DNS infrastructure."

Currently, it's unknown who was behind the attacks.

White House spokesman Josh Earnest said the US Department of Homeland Security is monitoring this situation and will take a close look at it.

"But at this point, I don't have any information to share about who may be responsible for that malicious activity," Earnest told reporters.

A senior US intelligence official told NBC News as quoted by Xinhua, that their current assessment is that this is "a classic case of internet vandalism."

The official was quoted as saying that it does not appear at this point to be any kind of state-sponsored or directed attacks. --BERNAMA