Experts are advising infected users not to pay the ransom, because it is unlikely they will get their files back. The attack began in the afternoon of Friday, May 12.
National Health Service: At least sixteen NHS organizations have been hit, according to NHS Digital.
Severe data breaches, those that become public and had legal or regulatory consequences, caused share prices to fall by an average of 1.8 per cent, the analysis of 65 companies affected since 2013 found. Finance sector companies were the worst hit, followed by communications groups.
"This one, we knew it could be a problem", the official told Reuters."NSA should be embarrassed - they've had a lot of damaging leaks", said James Lewis, a former USA official who is now a cyber expert at the Center for Strategic and International Studies.
As a loose global network of cybersecurity experts fought the ransomware hackers, Chinese state media said 29,372 institutions there had been infected along with hundreds of thousands of devices.
"The recent Ransomware attack has taken the world by storm but it is also the biggest Ransomware attack in the human history".
The WannaCry ransomware sweeping the world hasn't stopped its progress, but quick action by cybersecurity professionals has at least partially limited the damage it does as it goes.
"The infection of one computer triggers rather remotely the infection of entire networks", Wainwright said.
"Our banks may be affected in a couple of hours".
Meanwhile, in Europe the situation appears to have stabilized, according to Jan Op Gen Oorth, a spokesperson for Europol.
The attack crippled a number of hospitals in the United Kingdom and essential gas, telecommunications and water utilities in Spain.
The government has already activated a "preparedness and response mechanism" to prevent any major cyber attack.
Security solutions providers have also accelerated efforts to develop tools to tide over the crisis.
Computers around the globe were hacked beginning last Friday using a security flaw in Microsoft's Windows XP operating system, an older version that was no longer given mainstream technical support by the U.S. computing giant. It must, in any case, be noticed that this program could just hack into PCs reliant on the Microsoft Windows working operating system.
While the initial fix slowed down the progress of the virus, researchers say that two new variations have surfaced.
The use of that domain is being called a "kill switch" in the malware. The good news is that it only works partially.
The cyber criminals have demanded a fee of about $300 in crypto-currencies like Bitcoin for unlocking the device. Despite the attack being widespread, it's estimated that only about $32,000 were raised by the hackers.
This isn't the first time USA spy agencies have been accused of knowing about vulnerabilities and keeping them secret.