A "non-state actor" appeared to be behind a disruption of the internet on Oct. 21, according to the director of National Intelligence, James Clapper.
"The investigation is still going on. There's a lot of data to be gathered here. That appears to be preliminarily the case. But I wouldn't want to be conclusively definitive as to who it was," whether a nation-state was behind it or not, according to Clapper in an interview at the Council on Foreign Relations in New York.
A nation-state actor would be Russia or China, Clapper said.
The attack hacked many Internet-capable devices and flooded traffic toward one of the hosting firms for U.S. sites such as Twitter, Netflix, PayPal, and Spotify.
When the internet began, "security was never an integral part of what the Internet was designed for," Clapper said in the interview.
A collective calling itself New World Hackers claimed responsibility for the attack, but those claims were not verified, according to CBS News.
"We didn't do this to attract federal agents, only test power," two members of the collective said in a direct Twitter message with an AP reporter, according to CBS.
Network experts are starting to rule out national governments and online blackmailers. Allison Nixon, a researcher at online security firm Flashpoint, told the Wall Street Journal.
"All the arrows point away from any sort of political motivation. Of course, you never know until someone's got handcuffs on them," Nixon said.
The likelihood of more hacker attacks is high, Akamai Technologies Inc. analyst Martin McKeay told the Journal. Mirai code is one piece of software that has been identified as being used in the attacks, but that code won't be used for long.
"I would be surprised if Mirai lasted in its current incarnation for more than a few months, but something else will replace it," McKeay said.