The U.S. government is publicly acknowledging that North Korea was behind the WannaCry computer worm that affected more than 230,000 computers in over 150 countries earlier this year.
It was the North's fastest expansion for 17 years as Pyongyang quietly allows the market to play a greater role in its economy under Kim Jong-Un, even while denying it is carrying out reforms.
Bossert, who advises the president on homeland security, said the allegation was "based on evidence". "We are not alone with our findings, either".
Bossert said the finding was based on evidence and that it had been confirmed by other governments and private companies, including the United Kingdom and Microsoft.
The White House is expected to give an official statement blaming Pyongyang on Tuesday.
"The public opinion opposed to the preemptive attack is getting stronger in the U.S. It can be viewed as a sort of advice that the U.S. administration should drop the adventurous and risky way of thinking and boldly make a U-turn in its policy toward the DPRK", the commentary read, referring to North Korea by an acronym for its official name-the Democratic People's Republic of Korea.
"Having a formal report gives more weight to negotiations when the US approaches China, or Russian Federation or anywhere else that might be providing North Korea with internet services", Uren said.
He called on governments and companies around the world to cooperate to mitigate cyber risk, and said the US should lead the effort.
After WannaCry began infecting computers powered by Microsoft Corp.'s Windows via the internet on May 12, users had 72 hours to pay $300 in bitcoin, or pay twice as much. What made WannaCry particularly devastating was that it managed to spread itself like a computer worm to over 200,000 machines through the use of stolen NSA cyberweapons.
It said the Central Intelligence Agency had already laid blame on North Korea for the attack in November, though the assessment was classified and had not yet been previously reported.
But, the US government has assessed with a "very high level of confidence" that a hacking entity known as Lazarus Group, which works on behalf of the North Korean government, carried out the WannaCry attack, senior officials told Reuters.
Some researchers have said they believed WannaCry was deployed accidentally by North Korea as hackers were developing the code. Earlier this year, President Donald Trump promised to bring "fire and fury" on North Korea if it took actions that threatened the USA and other countries.