On May 12, 2017, the WannaCry ransomware spread to over 200,000 computers in 150 countries, locking hospitals, businesses, and governments out of their systems.
On this day in 2017, the WannaCry ransomware swept across the internet, locking more than two hundred thousand computers in about a hundred and fifty countries within a single day. It encrypted files and demanded payment, and it spread on its own from machine to machine, needing no one to click anything once it was loose.
The real-world cost landed hardest on places that could least afford downtime. Hospitals in the United Kingdom canceled operations and turned away patients because the systems holding records and scans were frozen. The attack exploited machines that had not installed a security update released weeks earlier.
The lesson reaches every household now that daily life runs on screens. Backups kept offline, prompt updates, and a plan for how you would function if your accounts and devices were suddenly locked are the personal version of defending against this kind of man made disaster.