Vulnerability Exploited: The attack took advantage of a vulnerability in Microsoft Windows, specifically targeting the SMB (Server Message Block) protocol. The exploit, known as "EternalBlue," was reportedly developed by the NSA and leaked by a hacking group.

Mechanism of Attack: WannaCry ransomware encrypted files on infected computers and demanded a ransom payment in Bitcoin to decrypt them. It used the exploit to spread to other vulnerable systems on the same network or across the internet.

Propagation: The ransomware was designed to spread automatically within networks and across the internet, leveraging the SMB vulnerability to infect additional computers rapidly.

Global Reach: The attack affected over 200,000 computers in more than 150 countries, making it one of the most widespread ransomware incidents in history.

Affected Entities: Major organizations were hit, including hospitals (notably the UK's National Health Service), government agencies, and various businesses, causing significant operational disruptions.

Financial Consequences: The attack led to substantial financial losses due to downtime, data recovery efforts, and ransom payments. Estimates of the total economic impact run into hundreds of millions of dollars.

Immediate Actions: Security researchers identified a "kill switch" in the ransomware’s code, which was a domain name that, when registered, halted further infections. This discovery slowed the attack's spread significantly.

Patch Release: Microsoft responded by releasing emergency security patches for supported and unsupported versions of Windows to close the exploited vulnerability and prevent further infections.

Long-Term Measures: The incident emphasized the need for regular software updates, enhanced cybersecurity practices, and improved network security measures to protect against similar attacks in the future. It also highlighted the importance of incident response planning and backups.