But the aftershocks have so far been mild.
The phenomenon of companies failing to update their systems has been a persistent security problem for years.
The 200,000 victims included more than 100,000 organizations, Europol spokesman Jan Op Gen Oorth told The Associated Press.
Unfortunately, having identified the flaw, the agency lost the information before it could devise any counter measures, prompting calls from Smith for 'a new requirement for governments to report vulnerabilities to vendors, rather than stockpile, sell, or exploit them'. The hackers exploited software code from the National Security Agency that leaked online.
"I think $20,000 to $30,000 worth", said Rob Wainwright, the director of Europol.
"There are other criminals who've launched this attack, and they are ultimately responsible for this", he said.
The blame game has already started.
Microsoft's president called on the government to apply the same rules it would to weapons in the physical world to viruses in cyberspace.
The names of the Australian businesses hit have yet to be named but are not critical infrastructure of government departments, Tehan said. "An equivalent scenario with conventional weapons would be the USA military having some of its Tomahawk missiles stolen".
At least one strain of the ransomware has proven especially vicious. That was "unheard of six months ago", Levy said.
The attack targets Windows systems that have not been udpated to patch the vulnerability revealed in the NSA leaks.
There are different variants of what happens: Other forms of ransomware execute programs that can lock your computer entirely, only showing a message to make payment in order to log in again.
Gas stations: State-run media in China reported that some gas stations saw their digital payment systems shut down, forcing customers to bring cash.
Also hit were Deutsche Bahn, the Russian Central Bank, Russian Railways, Russia's Interior Ministry, Megafon and Telefónica. Microsoft said the decision was based on protecting the Windows ecosystem itself, which seems sensible given the backlash will affect all of Windows's reputation.
He said tech companies, customers and the government need to "work together" to protect against attacks. The Indian government's Computer Emergency Response Team (CERT-in) has issued an alert and, in a late night email, announced an informational webcast about WannaCry scheduled at 11am today.
The company also reiterated a call it made earlier this year for an global agreement among states to shield civilians and corporate noncombatants from hacking. He said the situation was under control.
The U.K. National Health Service (NHS) was among the worst hit organisations, forcing hospitals to cancel appointments and delay operations as they could not access their patients' medical records.
How can a WannaCry victim regain access to data? . "We will continue to work with affected (organizations) to confirm this", the agency said. "Once upgraded, the windows operating system becomes more secure", he said.