The U.K. government believes North Korea was behind the “WannaCry” ransomware attack that took down large portions of the National Health Service and hundreds of thousands of other computers across the globe, Security Minister Ben Wallace said on Friday.
“North Korea was the state that we believe was involved in this worldwide attack on our systems,” Mr. Wallace told BBC radio.
He declined to go into “intelligence matters” but said “it is widely believed in the community and across a number of countries that North Korea had taken this role.”
WannaCry ultimately infected some 300,000 computers worldwide in May, locking users’ files and demanding they pay a $300 ransom to retrieve them.
In a report released on Friday, the U.K. National Audit Office said the attack affected 236 NHS trusts, forcing ambulances to be diverted and the cancellation of 19,000 medical appointments across the country. The office said NHS could have prevented the attack by following better IT security practices, Reuters reported.
On Thursday, NHS Lanarkshire said a missed security patch had left its systems vulnerable to the malware. WannaCry affected 11 of Scotland’s 14 health boards.
WannaCry was included among purported NSA hacking tools leaked in April by a group calling itself Shadow Brokers. The software exploited unpatched vulnerabilities in the Microsoft operating system that allowed it to spread to more than 75 countries in a matter of hours and 150 within days.
In August, the FBI indicted Marcus Hutchins, the 23-year old U.K. man who developed the “kill switch” that stopped WannaCry from spreading further. He has been charged with developing another malicious program called Kronos.