Let’s start with defining ransomware in general. Ransomware is a category of malware that locks your files or systems and holds them hostage for ransom. Ryuk is a type of ransomware used in targeted attacks, where the threat actors make sure that essential files are encrypted so they can ask for large ransom amounts. A typical Ryuk ransom demand can amount to a few hundred thousand dollars. Malwarebytes detects it as Ransom.Ryuk. For a more in-depth technical look at this threat, see our Ryuk ransomware threat spotlight.