.. /coregen.exe
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Execute (DLL)
AWL bypass (DLL)

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:

Resources:

Acknowledgements:

Detections:

Execute

  1. Loads the target .DLL in arbitrary path specified with /L.

    coregen.exe /L C:\folder\evil.dll dummy_assembly_name
    Use case
    Execute DLL code
    Privileges required
    User
    Operating systems
    Windows
    ATT&CK® technique
    T1055
    Tags
    Execute: DLL
    This LOLBAS executes Dynamic-Link Libraries (DLLs).

  2. Loads the coreclr.dll in the corgen.exe directory (e.g. C:\Program Files\Microsoft Silverlight\5.1.50918.0).

    coregen.exe dummy_assembly_name
    Use case
    Execute DLL code
    Privileges required
    User
    Operating systems
    Windows
    ATT&CK® technique
    T1055

AWL bypass

  1. Loads the target .DLL in arbitrary path specified with /L. Since binary is signed it can also be used to bypass application whitelisting solutions.

    coregen.exe /L C:\folder\evil.dll dummy_assembly_name
    Use case
    Execute DLL code
    Privileges required
    User
    Operating systems
    Windows
    ATT&CK® technique
    T1218
    Tags
    Execute: DLL
    This LOLBAS executes Dynamic-Link Libraries (DLLs).