Ransomware is a type of malicious software, or malware. After being downloaded to a server or a user’s computer, ransomware encrypts files on the device, blocking access and rendering files unusable until a ransom is paid. Versions like REvil and WannaCry ransomware are responsible for some of the largest and most devastating cyberattacks. Ransomware may be spread through Trojan files in an email that appears to be legitimate, but actually contains malware. Botnets like the massive Meris botnet may also be used to propagate ransomware or find vulnerabilities that can be exploited by ransomware gangs.