A day after a ransomware worm infected 75,000 machines in 100 countries, Microsoft is taking the highly unusual step of issuing patches that immunise Windows XP, 8, and Server 2003. These are operating systems the company stopped supporting as many as three years ago.
The attack on Friday affected many National Health Service hospitals in the UK and up to 70,000 devices including computers, MRI scanners, blood-storage refrigerators and theatre equipment. The NHS had to turn away non-critical emergencies.
Nissan UK, one of Europe's most productive car manufacturing plants, halted production after the ransomware infected their systems.
Microsoft have issued a patch for the vulnerability to all supported versions of Windows including Vista, 7 and 8.1 in March of this year. Windows 10 was never vulnerable.