One after another the calls came in from hospitals; criminals were infecting computer networks in a mass hack that was putting countless lives at risk. At Bucharest's national cyber-security centre (DNSC) they watched helplessly as the hackers spread across Romania through a popular piece of medical software. Cyber-chief Dan Cimpean had a tough decision to make, but it was the only option they had. The order went out to more than 100 hospitals. Disconnect from the internet, now. The cyber-