It may have saved governments and companies millions of dollars and slowed the outbreak before USA -based computers were more widely infected.
"While the spread of the Ransomware appears to have temporarily slowed, it is still critical that businesses and individuals patch the operating systems on their computers", the centre said in a statement on its website yesterday.
In a story May 14 about the global "ransomware" cyberattack, The Associated Press reported erroneously that the researcher known as MalwareTech had redirected the attacks to his server.
The ransomware attack struck British National Health Service organisations, along with computer networks of companies and municipalities in dozens of other countries.
Chinese state media said 29,372 institutions there had been infected along with hundreds of thousands of devices.
Russia's interior ministry said some of its computers had been hit by a "virus attack" and that efforts were underway to destroy it.
Among those affected by the virus was Nissan, but the auto manufacturer said there had been no major impact.
"There has been one incident of the ransomware hitting a business here in Australia and there could be two other incidents where it has occurred although we're trying to confirm that", he said. Home Secretary Amber Rudd said all but six of the NHS trusts back to normal Saturday.
Patients arriving at Dharmais Cancer Hospital had to wait several hours while staff worked with paper records.
"But our immediate priority as a government is to disrupt the attack, restore affected services as soon as possible, and establish who was behind it so we can bring them to justice".
The ransomware is spread by taking advantage of a Windows vulnerability that Microsoft released a security patch for in March.
Paying ransom will not ensure any fix, said Eiichi Moriya, a cybersecurity expert and professor at Meiji University.
"There's nothing you can do but pay once you're hit", Camacho said in an interview.More news: Snap Chat maintained as Hold By Canaccord Genuity
A FedEx spokesperson confirmed to ABC News that it was among the victims of the attack. The security researcher has posted an online account of finding the kill switch, which was also posted to the United Kingdom government's National Cyber Security Centre website.
He also warned hackers could upgrade the virus to remove the "kill switch" that helped to stop it.
While the researcher is being lauded online for helping to prevent a more widespread outbreak, MalwareTech doesn't consider themselves a hero.
He said: "We have been concerned for some time that the healthcare sectors in many countries are particularly vulnerable".
We first heard about WannaCry last week from the UK's health service, which appeared to be one of the first major computer systems affected by the hack.
Hong Kong-based Ivezic said that the ransomware was forcing some more "mature" clients affected by the worm to abandon their usual cautious testing of patches "to do unscheduled downtime and urgent patching, which is causing some inconvenience".
An unprecedented global "ransomware" attack has hit at least 100,000 organizations in 150 countries, Europe's police agency said Sunday - and predicted that more damage may be seen Monday as people return to work and switch on their computers.
Microsoft's top lawyer is laying some of the blame at the feet of the US government.
The culprits used a digital code believed to have been developed by the US National Security Agency - and subsequently leaked as part of a document dump, according to researchers at the Moscow-based computer security firm Kaspersky Lab.
The head of Turkey's Information and Communication Technologies Authority or BTK says the nation was among those affected by the ransomware attack.
He said it was too early to say who is behind the onslaught and what their motivation was. He said the main challenge was the fast-spreading capabilities of the malware, but added that, so far, not many people have paid the ransoms that the virus demands.
"Right now, just about every IT department has been working all weekend rolling this out", said Dan Wire, spokesman at Fireeye Security.
This one worked because of a "perfect storm" of conditions, including a known and highly risky security hole in Microsoft Windows, tardy users who did not apply Microsoft's March software fix, and malware created to spread quickly once inside university, business or government networks.