A hacking group linked to North Korea is thought to be behind the cyber attack that wreaked havoc across the globe, according to security experts.
Analysts from security firms Symantec and Kaspersky revealed that they are looking into technical clues suggesting the Lazarus Group created the virus.
The ransomware – which encrypts victims’ files then demands a fee to unlock them – left Britain’s health service crippled as computer systems and phone lines across the country shut down on Friday.
The NHS is still struggling to get back on its feet following the attack, which means patients could have to wait a month or more to see a doctor after countless operations and appointments were cancelled.
The global cyber attack brought the NHS to its knees on Friday and over the weekend
Symantec and Kaspersky said code in an earlier version of the WannaCry ransomware had also appeared in other malicious software created by those hackers.
The Lazarus Group has already been blamed for a string of hacks dating back to at least 2009, including last year’s $81 million heist from Bangladesh’s central bank.