What is ransomware?

Attackers usually get in through phishing emails, stolen passwords or unpatched software, then encrypt files and demand payment, often in cryptocurrency. Many gangs now also steal data and threaten to publish it, a tactic called double extortion. The 2017 WannaCry attack spread to more than 200,000 computers in about 150 countries, disrupting parts of the UK’s National Health Service. In 2021, an attack on Colonial Pipeline caused fuel shortages along the US East Coast. Experts advise regular offline backups, software updates and 2FA, and many authorities discourage paying ransoms.