The flaw in Windows behind a huge cyber-attack affecting organisations around the world, including some United Kingdom hospitals, can be traced back to the US National Security Agency (NSA) - raising questions over the US government's decision to keep such flaws a secret.

WannaCry takes advantage of a vulnerability in Microsoft Windows.

In March, Microsoft unveiled a patch to address the issue, but several users are yet to have their systems updated.

Internationally, China reported of 40,000 organisations being impacted, while the National Health Service of the United Kingdom was also hit badly. The attack since has been believed to be halted, by an anonymous specialist known only as MalwareTech. They are attacking the old and outdated Windows version, like the Windows XP.

"When you buy a computer and it does most of the work for you, that's probably the best solution", he said.

"Hopefully people are learning how important it is to apply these patches", said Darien Huss, a senior security research engineer for cybersecurity firm Proofpoint, who helped stem the reach of the weekend attack. The malware spreads through email.

With regards to the threat of further ransomware attacks, the only real way that they can be prevented would be to patch every single vulnerability that the perpetrators could target with the worm.

As Fox News previously reported, the malware was detected as early as March and was publicly reported as stolen from the National Security Agency a month later. "We need governments to consider the damage to civilians that comes from hoarding these vulnerabilities and the use of these exploits". Cybereason watches for the start of encryption activity and immediately stops it. Windows installations that aren't verified as genuine are prevented from accessing Windows Update. In the case of ATMs, there is no data stored in the machine. Install all Windows updates. 5. Microsoft also took the unusual step of releasing security fixes for systems it no longer is keeping up to date, including the Windows XP, first released in 2001 and still widely used in some corners.

"We do backups multiple times a day, so we have an option of which backup to go back to", Rodriguez said, adding later that there are over 20,000 attempted computer attacks on the county daily.

For those running Windows 10 or Windows Vista, Windows 7 and Windows 8.1 systems, which has automatic updates turned on, you'll remain protected from WannaCry. The same problem exists with industrial equipment and devices that are part of the critical infrastructure.

"A large-scale infection has been avoided, thanks to a 72-hour national mobilization and emergency response led by the authorities and supported by the industry", leading domestic cyber security company 360 Business Security Group said.