British security officials said that hackers in North Korea were behind the cyberattack that crippled parts of the National Health Services (NHS) and other organisations around the world last month, the media reported.
Officials from the National Cyber Security Centre (NCSC) told the BBC on Thursday that they believe that the North Korea-based hacking group known as Lazarus launched the attack. It is also believed to have targeted Sony Pictures in 2014.
The Sony hack came as the company planned to release the movie "The Interview", a satire about an assassination attempt on North Korean leader Kim Jong-un. The movie was eventually given a limited release after an initial delay.
The Lazarus group has also been linked to the use of ransomware including against a South Korean supermarket chain. In May, ransomware called WannaCry swept across the world, locking computers and demanding payment for them to be unlocked. The NHS in the UK was particularly badly hit.
NCSC officials began their own investigation and concluded their assessment, reports the BBC.
The ransomware did not target Britain or the NHS specifically, and may well have been a money-making scheme that got out of control, particularly since the hackers do not appear to have retrieved any of the ransom money as yet.