CryptoDefense Ransomware

CryptoDefense is a sophisticated subset of CryptoLocker ransomware that first appeared in 2014. It employed public-key cryptography (PKC) and targeted computers running the Windows operating system (OS). The infection was spread via spam emails containing infected PDF documents. Victims were often given 72 hours to pay a ransom, collected largely in bitcoin (BTC), in order to regain access to their infected files, which would otherwise be permanently deleted.