A massive ransomware attack, believed to be the biggest in history, has affected nearly 100 countries worldwide. The attack, which started on May 12, 2017, targets older versions of Microsoft Windows and demands payments of $300 to $600 in exchange for restoring access to locked computers. The malware spreads through email attachments and exploits a vulnerability in Windows, taking advantage of unpatched systems. The attack has caused significant disruptions, particularly in the healthcare sector, with hospitals in Britain and other countries forced to turn away patients. Cybersecurity experts are warning that this is an unprecedented and highly sophisticated attack that requires immediate attention.