"North Korea has acted especially badly, largely unchecked, for more than a decade, and its malicious behavior is growing more egregious".
Pyongyang has previously denied being responsible for the attack.
Bossert said that the USA would "publicly attribute" WannaCry to North Korea, describing the attacks as "cowardly" and "careless".
The attack exploited a Windows vulnerability that was originally developed by the US National Security Agency, but was released in a stolen cache of NSA cyberweapons by hacking group known as the Shadow Brokers. Hutchins was able to trip that switch, and the attack soon ended.
Bossert closes out his article by stating that North Korea "continues to threaten America, Europe and the rest of the world - and not just with its nuclear aspirations".
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The North Korean soldier, 24-year-old Oh Chong Song, was transferred to the military hospital last Friday from a trauma centre at Ajou University Hospital, south of Seoul, where his treatment for gunshot wounds and pre-existing conditions included two major operations. Seoul's Defense Ministry earlier said North Korea was likely behind the hacking of the Defense Integrated Data Center, which is the military data center where the information was kept, in September previous year but refused to confirm the nature of the information that was compromised.
Bossert also called the attack reckless, while Reuters cites a "senior administration official" who declined to comment on whether or not the usa believes it was a deliberate attack or accidental.
Lazarus Group have in the past been accused of being responsible for the 2014 hack of Sony Pictures Entertainment that destroyed files, leaked corporate communications and led to the departure of top studio executives. "The United Kingdom attributes the attack to North Korea, and Microsoft traced the attack to cyber affiliates of the North Korean government".
"We are monitoring the bitcoin-related issue".
Last week, US Secretary of State Rex Tillerson said that Washington would be willing to talk to Pyongyang without the precondition of North Korea's denuclearisation, reports Efe news.