CryptoLocker

CryptoLocker was a notorious piece of ransomware that emerged in 2013. It was one of the first prominent examples of ransomware that used strong encryption to lock users' files, demanding payment in Bitcoin for the decryption key. The malware typically spread through email attachments, often disguised as invoices or shipping notifications. Once executed, CryptoLocker would scan the infected computer for specific file types, such as documents, images, and videos, and encrypt them. A ransom note would then appear on the screen, informing the user that their files were inaccessible and providing instructions on how to pay the ransom, usually within a strict time limit.

The financial demands varied, but commonly ranged from a few hundred to several thousand dollars. Failure to pay within the given timeframe would often result in the ransom amount doubling or the decryption key being permanently destroyed, making data recovery impossible without a backup. Security researchers and law enforcement agencies worked to combat CryptoLocker, and various decryption tools were eventually developed for some versions of the malware, particularly those that did not have robust key management. However, CryptoLocker's success highlighted the growing threat of ransomware and prompted significant advancements in cybersecurity defenses against such attacks. Its impact led to increased awareness about the importance of regular backups and cautious online behavior.