[Rubeus](https://attack.mitre.org/software/S1071) is a C# toolset designed for raw Kerberos interaction that has been used since at least 2020, including in ransomware operations.(Citation: GitHub Rubeus March 2023)(Citation: FireEye KEGTAP SINGLEMALT October 2020)(Citation: DFIR Ryuk's Return October 2020)(Citation: DFIR Ryuk 2 Hour Speed Run November 2020)