Experts say the spread of the virus had been stymied by a security researcher in the U.K. Hackers have issued new versions of the virus that cyber security organizations are actively trying to counter and stamp out. He added that the agency is still analyzing the virus and has yet to identify who is responsible for the attack.
The software, which first affected Britain's National Health Service before spreading to as many as 150 countries, locked down victims' computers and threatened to delete their files unless they paid $300.
"My answer is, never pay the ransom", Lawrence Abrams, a New York-based blogger who runs BleepingComputer.com told The Associated Press.
Defence minister Michael Fallon told the BBC the government under Prime Minister Theresa May was spending around 50 million pounds on improving the computer systems in the NHS after warning the service that it needed to reduce its exposure to "the weakest system, the Windows XP".
"The US government clearly had its priorities wrong".
Europol's Wainwright underscored the point Sunday. When the leaks occurred, Microsoft patched the vulnerability, but the events that kicked off on Friday demonstrated that many, many systems weren't up to date.
The ransomware campaign - which has gone through at least two phases as researchers worked to halt its advance - mostly affected Europe and Asia.
In order to prevent infection, users and organisations are advised to apply patches to Windows systems as mentioned in Microsoft Security Bulletin MS17-010, it said.
A full scan should be carried out - this will locate any malware that may have already found its way onto your computer.
The company said they had released a security update back in March to protect Window system computers against such attacks, but said many computers "remained unpatched globally". Some have also been machines involved in manufacturing or hospital functions, hard to patch without disrupting operations.
Earlier today, Brad Smith posted a blog looking at the broader implications of the malicious "WannaCrypt" software attack that took place over the last few days.
Europol executive director Rob Wainwright said the situation could worsen on Monday when workers return to their offices after the weekend and log on.
Outside of the damage being done by blocking access to essential services, financial repercussions, and productivity slowdowns, this is an global incident that is likely causing diplomatic rifts with our allies.
The effects were felt across the globe, with Britain's National Health Service, Russia's Interior Ministry and companies including Spain's Telefonica, FedEx Corp.in the US and French carmaker Renault all reporting disruptions. Although no ransom was being demanded, the company suspected the WannaCry ransomware cyberattack of causing the disturbances.
"The government's response has been chaotic, to be frank", the British Labour Party's health spokesman Jon Ashworth said. Windows Defender identifies it as Ransom:Win32/WannaCrypt, and can effectively remove the malware from your system. Two big telecom companies, Telefónica of Spain and Megafon of Russian Federation, were also hit, as was Japanese carmaker Nissan in the United Kingdom. It said less than 1% of computers were affected, and that the virus was now "localized" and being destroyed.
It said Sunday that a similar cyberattack could also recur, though it did not have "specific evidence" of this.
The relatively new group now has the unenviable task of cleaning up the NSA's mess, and protecting systems in the US from further attacks. They need to take a different approach and adhere in cyberspace to the same rules applied to weapons in the physical world.
Security researchers started dissecting WannaCry as soon as it popped up, among them a man who goes by MalwareTech. Here's how to turn automatic updates on.
India's cyber security agency has alerted Internet users against damaging activities of "WannaCry"- that critically infects work stations and locks them remotely.