The malicious software appeared to exploit a vulnerability in Microsoft Windows that was supposedly identified by the US National Security Agency for its own intelligence-gathering purposes and was later leaked to the internet.
The United Kingdom's National Health Service was hit hard, its hospitals forced to close wards and emergency rooms.
Russian Federation appeared to be the hardest hit nation, with its interior and emergencies ministries and biggest bank, Sberbank, saying they were targeted.
While we'd often advise people infected by ransomware to contact the police before paying any sort of ransom - mainly because there's no guarantee that the malicious users behind the malware will release your data even if they get paid - the NHS doesn't have that luxury considering lives could be at stake.
Numerous state and private institutions affected are mainly in Asia and Europe, but the ransomware, which experts are calling WannaCry, has also spread to North America and South America. In the case of WannaCry, the program encrypts your files and demands payment in bitcoin in order to regain access.
British based cyber researcher Chris Doman of AlienVault said the ransomware "looks to be targeting a wide range of countries", with initial evidence of infections in at least two dozen nations according to experts from three security firms.
Only a small number of US -headquartered organizations were hit because the hackers appear to have begun the campaign by targeting organisations in Europe, said Thakur.
Hacking group Shadow Brokers reportedly released the malware last month, after claiming to have discovered the flaw from the US National Security Agency. Several cyber security firms said WannaCry exploits a vulnerability in Microsoft and that Microsoft patched this in March.
By the group's count, the malware struck at least 74 countries.
Affected hospitals are postponing all non-urgent activity and are asking people not to come to A&E. Doctors' practices and pharmacies reported similar problems.
At least 74 countries affected in 'biggest ever' cyber attack
A major cyber attack on NHS hospitals across the country is causing a weekend of chaos for London patients and medics. The National Cyber Security Centre (NCSC) said teams were "working round the clock" in response to the attack.
"Both staff and patients were frankly pretty appalled that somebody, whoever they are, for commercial gain or otherwise, would attack a health care organization", he said.
British Home Secretary Amber Rudd said Saturday that 45 public health organizations were hit, but she stressed that no patient data had been stolen.
"We are very aware that attacks on critical services such as the NHS have a massive impact on individuals and their families, and we are doing everything in our power to help them restore these vital services", he said.
Elsewhere in Europe, the ransomware outbreak hit phone company Telefonica, Vodafone and energy supplier Iberdrola in Spain.
Ransomware attacks are on the rise around the world.
Non-emergency operations have been suspended at Chorley and Preston hospitals this weekend after a virus targeted the health service network and affected systems across the country.
"Looking at the trends, it was going to happen", he said.
Cyber-experts were left stunned by the scale of the worldwide ransomware attack, reports the Herald. That was a shock.
Organisations in Belgium, France and Italy were also attacked, and Russia's interior ministry said 1000 of its computers had been infected. Parra reported from Madrid.
Comments