Launched in 2013, CryptoLocker encrypted files on infected PCs and demanded Bitcoin payment. It spread through email attachments and peer-to-peer networks. Victims had a short window to pay before files were lost. The attack reportedly netted millions of dollars. Its success inspired countless variants. CryptoLocker popularized the ransomware-as-a-service model.
It matters because it set the blueprint for modern ransomware. Its impact is still felt today.
It also accelerated adoption of cryptocurrency in criminal activity.
CryptoLocker was the first widely successful ransomware to demand Bitcoin payment.
[Europol, europol.europa.eu]