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Fsi (f2a5e6cb-75fd-4108-9466-80471c7d0422)

This object contains information sourced from the Living Off The Land Binaries, Scripts and Libraries (LOLBAS) project, which is licensed under GNU General Public License v3.0.

Description: 64-bit FSharp (F#) Interpreter included with Visual Studio and DotNet Core SDK.

Author: Jimmy (@bohops)

Paths: * C:\Program Files\dotnet\sdk[sdk version]\FSharp\fsi.exe * C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\Common7\IDE\CommonExtensions\Microsoft\FSharp\fsi.exe

Resources: * https://twitter.com/NickTyrer/status/904273264385589248 * https://bohops.com/2020/11/02/exploring-the-wdac-microsoft-recommended-block-rules-part-ii-wfc-fsi/

Detection: * Elastic: defense_evasion_unusual_process_network_connection.toml * Elastic: defense_evasion_network_connection_from_windows_binary.toml * BlockRule: https://docs.microsoft.com/en-us/windows/security/threat-protection/windows-defender-application-control/microsoft-recommended-block-rules * IOC: Fsi.exe execution may be suspicious on non-developer machines * Sigma: proc_creation_win_lolbin_fsharp_interpreters.yml[Fsi.exe - LOLBAS Project]

Cluster A Galaxy A Cluster B Galaxy B Level
Fsi (f2a5e6cb-75fd-4108-9466-80471c7d0422) Tidal Software Chimera (ca93af75-0ffa-4df4-b86a-92d4d50e496e) Tidal Groups 1
Fsi (f2a5e6cb-75fd-4108-9466-80471c7d0422) Tidal Software Turla (47ae4fb1-fc61-4e8e-9310-66dda706e1a2) Tidal Groups 1