A simple POC to show the power of .NET debugging capabilities when looking to inject code without an unmanaged stub.

It is recommended that you build this POC in x64 mode for best results. This can be done via Visual Studio or MSBuild using the following:

msbuild.exe DotNetDebug.sln /property:Platform=x64 

This tool can be run in the following modes:

• attach - Attaches to a running process by name
• attachpid - Attached to a running process via PID
• launch - Launches a new process and attaches the debugger on start

By default, the injected .NET payload will attempt to load an assembly from C:\Windows\Temp\inject.exe and execute its entrypoint.

For example:

DotNetDebug.exe launch C:\Windows\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe

Note: Ensure that if you are running the x64 version of the tool, you are only targeting x64 compiled .NET processes.

If you are struggling to get things attached, remember that there are 2 COMPlus variables which can come in handy:

set COMPlus_ZapDisable=1
set COMPlus_JITMinOpts=1

Set both of these before launching DotNetDebug.exe, seems to solve some issues when injecting into a x86 process.