Microsoft had already patched the exploit at the time of the attack - but because many organisations hadn't updated their software, they were still vulnerable.
Power firm Iberdrola and utility provider Gas Natural were also reported to have suffered from the outbreak. But computers and networks that didn't update their systems are still at risk.
Apple's Mac computers were not targeted by this ransomware attack so are clear.
Europol said Saturday that the attack was of an "unprecedented level and requires global investigation".
A cyber ransomware is a type of malicious software that blocks access to a computer system until a sum of money is paid through the online medium.
With his new statement, Smith seems to be confirming that version of events. Unfortunately, this tool, along with many others, was stolen by hackers and leaked to the world in April 2017 by a hacker group calling themselves the "Shadow Brokers".
A number of variants were spotted by different cyber security researchers.
Britain's National Health Service said about a fifth of NHS trusts - the regional bodies that run hospitals and clinics - were hit by the attack on Friday, leading to thousands of cancelled appointments and operations.
Chinese media reported that more than 29,000 institutions in the country had been hit, with universities and other educational entities the hardest hit, along with railway services and retailers.
Among those hit were the Russian Ministry of Internal Affairs and companies including Spain's Telefonica SA and FedEx Corp in the US.
One is a 22-year United Kingdom cybersecurity researcher, who goes by the name "Malware Tech", and the other is a Grand Rapids Security Research Engineer named Darien Huss. It had urged computer users to install and upgrade security software.
Lawrence Abrams, a New York-based blogger who runs BleepingComputer.com, says many organizations don't install security upgrades because they're anxious about triggering bugs, or they can't afford the downtime.
Consumers who have up-to-date software are protected from this ransomware.
Exploits in the hands of governments have repeatedly leaked into the public domain and caused widespread damage, wrote Smith, who compared the leaks of Central Intelligence Agency and NSA vulnerabilities to the US military having some of its Tomahawk missiles stolen. Here's how to turn automatic updates on.
Smith repeated a call he made in February, calling for an global convention on the use of cyberwarfare akin to the Geneva Conventions' protections for noncombatants and other guidelines in conventional warfare.
The NSA exploit codes were leaked earlier this year by the Shadow Brokers hacking group which had previously been offering the U.S. government cyber weapons in exchange for millions of dollars in Bitcoin.
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