Virlock is a file-infecting ransomware that was initially found in 2014 but reappeared in 2016 and 2017. Virlock revealed new abilities with each reappearance, showing that the threat actors are continually developing and updating the malware. It showed unique capabilities in 2016 that allowed it to expand through shared apps and cloud storage. During the initial stage of its attack, this ransomware drops three instances of itself, each with its own obfuscation and persistence techniques. By altering the functionality implemented by each instance, Virlock ensures that all three instances can evade a signature-based detection system. Virlock, like other ransomware, demands payment in Bitcoin from the victim in order to decrypt their machines.