[GuLoader](https://attack.mitre.org/software/S0561) is a file downloader that has been used since at least December 2019 to distribute a variety of remote administration tool (RAT) malware, including [NETWIRE](https://attack.mitre.org/software/S0198), [Agent Tesla](https://attack.mitre.org/software/S0331), [NanoCore](https://attack.mitre.org/software/S0336), FormBook, and Parallax RAT.(Citation: Unit 42 NETWIRE April 2020)(Citation: Medium Eli Salem GuLoader April 2021)