On May 12, 2017, hackers exploiting a vulnerability in Microsoft Windows have attacked a large number of PCs worldwide, including hospitals in the UK and elsewhere and have infected vulnerable PCs with “ransomware” demanding payment in order to unlock the infected computer. The malware propagates by tricking email recipients into clicking on infected attachments. Once a PC is infected it looks for other vulnerable Windows PCs on the local network and spreads further, so one infected PC can infect a whole LAN.
Microsoft patched this vulnerability in March – if you have your PC set to automatically download and install updates, you’re probably safe, but we advise that you go into Windows Update on your PC and check for updates and make sure that all available updates have been installed.
This exploit is sufficiently serious that Microsoft has released a patch that also covers Windows XP, which has been unsupported for some time. More information on the patch: Microsoft