Ransomware is a type of malicious software that locks users out of their system or data using different methods to force them to pay a ransom. Most often, such programs encrypt files on an infected machine and demand a fee to be paid in exchange for the decryption key. Additionally, such programs can be used to steal sensitive information from the compromised computer and even conduct DDoS attacks against affected organizations to pressure them into paying.

Virlock is a unique ransomware strain that combines encryption capabilities with file infection techniques. First observed in 2014, it stands out due to its polymorphic nature and ability to embed its code into compromised files, ensuring continued propagation. Once it infects a system, it encrypts files and locks the screen, demanding a ransom for file recovery and system access.