Animated map of how tens of thousands of computers were infected with ransomware https://t.co/LDFCW9K5Ls pic.twitter.com/E5Ep9KesaV

— The New York Times (@nytimes) May 13, 2017

The only thing that kept Friday's ransomware attack from being truly devastating was because of one lucky 22-year old IT worker in England.

“I was out having lunch with a friend and got back about 3pm and saw an influx of news articles about the NHS and various UK organisations being hit,” he told the Guardian. “I had a bit of a look into that and then I found a sample of the malware behind it, and saw that it was connecting out to a specific domain, which was not registered. So I picked it up not knowing what it did at the time.”
The kill switch was hardcoded into the malware in case the creator wanted to stop it spreading. This involved a very long nonsensical domain name that the malware makes a request to – just as if it was looking up any website – and if the request comes back and shows that the domain is live, the kill switch takes effect and the malware stops spreading. The domain cost $10.69 and was immediately registering thousands of connections every second...
He warned people to patch their systems, adding: “This is not over. The attackers will realise how we stopped it, they’ll change the code and then they’ll start again. Enable windows update, update and then reboot.”

The kid's warning could not be more true. Within 24 hours IT experts noticed new versions of the ransomware without the kill switch.

I will confess that I was unaware registering the domain would stop the malware until after i registered it, so initially it was accidental.

— MalwareTech (@MalwareTechBlog) May 13, 2017

Today security experts warned that Monday could get pretty ugly.

Security experts are warning that the global cyberattack that began on Friday is likely to be magnified in the new workweek as users return to their offices and turn on their computers.
Many workers, particularly in Asia, had logged off on Friday before the malicious software, stolen from the United States government, began proliferating across computer systems around the world. So the true effect of the attack may emerge on Monday as employees return and log in.
Moreover, copycat variants of the malicious software behind the attacks have begun to spread, according to experts. “We are in the second wave,” said Matthieu Suiche of Comae Technologies, a cybersecurity company based in the United Arab Emirates. “As expected, the attackers have released new variants of the malware. We can surely expect more.”
The cyberattack has hit 200,000 computers in more than 150 countries, according to Rob Wainwright, the executive director of Europol, the European Union’s police agency.

Obviously some people have pointed fingers at Russia, but that only proves that they don't know much about computers. Ransomware attacks are so pedestrian these days that you could pay for one.

There is even now a concept of “ransomware as a service” — a play on the Silicon Valley jargon “software as a service,” which describes the delivery of software over the internet.
Now anyone can visit a web page, generate a ransomware file with the click of a mouse, encrypt someone’s systems and demand a ransom to restore access to the files. If the victim pays, the ransomware provider takes a cut of the payment.
Ransomware criminals also have customer service lines that victims can call to get help paying a ransom. There are even live chat options. And while some amateur ransomware attackers may not restore victims’ data once the ransom is paid, the more professional outfits worry that if they do not decrypt a victim’s data, their reputation and “business” may suffer as a result, Mr. Rebholz said.

#WanaCypt0r#wannacrypt #infosec
China has been attacked to expand the scope pic.twitter.com/9ibYHavK52

— 95cn (@95cnsec) May 13, 2017

I'm a big SciFi fan, especially the old classics.
One of my favorite authors is Arthur C. Clarke.
One of his books, Rama II, is definitely not one of his better books and I don't recommend it, but it does open with an interesting premise.
It starts with the collapse of western civilization, not from war, plague, or environmental disaster, themes that are so overused by dystopian writes these days, but from a financial crisis that crashes the global computer systems. The interesting take is how no one has cash anymore, so if the banks and credit systems go down for a few weeks people go hungry and supply systems collapse.
A really effective computer virus could do the exact same thing. Not this one, obviously, but theoretically it is possible.

"Since cash had long ago become obsolete, only eccentrics and collectors had enough banknotes to buy even a week's groceries. People began to barter for necessities. Pledges based on friendship and personal acquaintances enabled many people to survive temporarily. But the pain had only begun.
...By the time normal electronic activity had been restored, the world was in a violent financial downspin that would not bottom out until twelve years later."
- Arthur C. Clarke