rcsi.exe

Commands

1. ExecuteUser T1127

   Local execution of arbitrary C# code stored in local CSX file.

   rcsi.exe {PATH:.csx}

   Use embedded C# within the csx script to execute the code.

   os: Windows

   Execute: CSharp

2. AWL BypassUser T1127

   Local execution of arbitrary C# code stored in local CSX file.

   rcsi.exe {PATH:.csx}

   Use embedded C# within the csx script to execute the code.

   os: Windows

   Execute: CSharp

Detection

• Sigma https://github.com/SigmaHQ/sigma/blob/c04bef2fbbe8beff6c7620d5d7ea6872dbe7acba/rules/windows/process_creation/proc_creation_win_csi_execution.yml
• Elastic https://github.com/elastic/detection-rules/blob/414d32027632a49fb239abb8fbbb55d3fa8dd861/rules/windows/defense_evasion_unusual_process_network_connection.toml
• Elastic https://github.com/elastic/detection-rules/blob/414d32027632a49fb239abb8fbbb55d3fa8dd861/rules/windows/defense_evasion_network_connection_from_windows_binary.toml
• BlockRule https://github.com/SigmaHQ/sigma/blob/c04bef2fbbe8beff6c7620d5d7ea6872dbe7acba/rules/windows/process_creation/proc_creation_win_csi_execution.yml

Resources

• https://enigma0x3.net/2016/11/21/bypassing-application-whitelisting-by-using-rcsi-exe/