[Ryuk](https://attack.mitre.org/software/S0446) is a ransomware designed to target enterprise environments that has been used in attacks since at least 2018. [Ryuk](https://attack.mitre.org/software/S0446) shares code similarities with Hermes ransomware.(Citation: CrowdStrike Ryuk January 2019)(Citation: FireEye Ryuk and Trickbot January 2019)(Citation: FireEye FIN6 Apr 2019)