coregen.exe
Binary coregen.exe (Microsoft CoreCLR Native Image Generator) loads exported function GetCLRRuntimeHost from coreclr.dll or from .DLL in arbitrary path. Coregen is located within "C:\Program Files (x86)\Microsoft Silverlight\5.1.50918.0\" or another version of Silverlight. Coregen is signed by Microsoft and bundled with Microsoft Silverlight.
Paths
C:\Program Files\Microsoft Silverlight\5.1.50918.0\coregen.exeC:\Program Files (x86)\Microsoft Silverlight\5.1.50918.0\coregen.exe
Commands
Execute
Loads the target .DLL in arbitrary path specified with /L.
Use case: Execute DLL code
Privileges: User
coregen.exe /L {PATH_ABSOLUTE:.dll} dummy_assembly_nameExecute
Loads the coreclr.dll in the corgen.exe directory (e.g. C:\Program Files\Microsoft Silverlight\5.1.50918.0).
Use case: Execute DLL code
Privileges: User
coregen.exe dummy_assembly_nameAWL Bypass
Loads the target .DLL in arbitrary path specified with /L. Since binary is signed it can also be used to bypass application whitelisting solutions.
Use case: Execute DLL code
Privileges: User
coregen.exe /L {PATH_ABSOLUTE:.dll} dummy_assembly_nameDetection
- Sigma: https://github.com/SigmaHQ/sigma/blob/b02e3b698afbaae143ac4fb36236eb0b41122ed7/rules/windows/image_load/image_load_side_load_coregen.yml
- IOC: coregen.exe loading .dll file not in "C:\Program Files (x86)\Microsoft Silverlight\5.1.50918.0\"
- IOC: coregen.exe loading .dll file not named coreclr.dll
- IOC: coregen.exe command line containing -L or -l
- IOC: coregen.exe command line containing unexpected/invald assembly name
- IOC: coregen.exe application crash by invalid assembly name