Europol says cyberattack that hit NHS is 'biggest in history and unique'

The cyberattack that crippled NHS computer systems is the biggest of its kind and "unique" in its malicious software, security chiefs have said.

Known as WannaCrypt or WannaCry, the ransomware is widely believed to have been developed as a hacking tool by the US National Security Agency.

In its latest update on the cyberattack, Europol said it was the "largest ransomware attack observed in history".

The EU's law enforcement body said the unique features of the WannaCry ransomware were its two main components, a "worm functionality" and the ransomware itself.

Europol said: "This is the first ever detected malware combining these features, which makes it unique."

Russia on Monday denied it had anything to do with the cyberattack.

President Vladimir Putin said there was "no significant damage" to Russian institutions such as banks and hospitals, but asserted the incident was "worrisome" and warranted immediate talks "on a serious political level".

:: Cyberattacks: How to protect your computer from infection

The NHS was among hundreds of organisations affected around the world, with 47 trusts hit.

Sky News has learned that trusts in England were sent details of a security patch last month to protect themselves from such an attack.

A spokesman for NHS Digital said: "Our understanding is that if that had been acted on it would have prevented (the malware attack)."

The cyberattack, which began in London on Friday morning, has so far affected 150 countries and locked more than 200,000 computers.

As people across the globe returned to work, Japan reported 2,000 computers at 600 locations had been affected, with firms including Hitachi and Nissan reporting problems.

Chinese state media said 29,372 institutions had been affected along with hundreds of thousands of devices, and universities and universities and schools among the hardest hit.

Microsoft said the attack was a "wake-up call" and identified "nation-state action and organised criminal action" as "the two most serious forms of cybersecurity threats in the world today".

The company said it had released a security update back in March to protect Windows system computers against such attacks, but said many computers "remained unpatched globally".

The 22-year-old British IT expert credited with saving thousands more computers across the world being infected said he was more concerned for his privacy than his safety.

The security researcher, who goes by the handle of MalwareTech (MT), was hailed an "accidental hero" for discovering the WannaCry virus' kill switch.

He tweeted on Monday: "For the record I don't 'fear for my safety', I'm just unhappy with trying to help clear up Friday's mess with the doorbell going constantly."

The online community pleaded for his identity not to be outed online - a research process known as "doxing" - to protect him.