Copies the current process image into a target process and begins execution on WinMain. Same concept as documented at https://www.ired.team/offensive-security/code-injection-process-injection/pe-injection-executing-pes-inside-remote-processes , but with slightly different implementation. This technique can also be expanded on to include DLL's as payloads instead of just the current PE (load DLL into current process then copy all bytes to target and remote thread on DLLMain).

This example shows how we can inject the current PE image into another running process and execute some payload. The injected code is undetected by most usermode anti-cheat systems and won't show up from DLL walking. The code example has been expanded to show how a working Win32 GUI can be spawned; the GUI can then be used for some other logic, providing us a foothold onto the target process.

1. Open the target process and allocate space greater or equal to the payload's image size using VirtualAllocEx
2. Take the address for our new allocated buffer and write over the NT Optional header's ImageBase member with this address
3. Traverse relocations table in local process and modify entries to account for the target process memory address
4. Copy all bytes from payload image to a buffer, write it into the target process using WriteProcessMemory after calling VirtualProtectEx
5. Calculate the offset to our image's main routine by subtracting the address of main from the payload's image base
6. Use the main offset (added with step 1's address) with CreateRemoteThread to make a new thread in our target process and begin program flow

In summary, this technique allocates some space in the target, writes the current process module bytes to it, finds the 'WinMain' or 'Main' or 'Dllmain' offset, then creates a remote thread at that offset to execute the payload.

1. A TLS callback can be used to prevent unknown threads being created in the target process.
2. Window Creation handles & registering window classes can be monitored for foreign GUIs, as we use CreateWindow to spawn a user-controllable interface in the target application.
3. Preventing foreign calls to OpenProcess from succeeding will make the entire technique fail

For this technique it's recommended to call WINAPI function pointers with their address calculated at runtime using GetProcAddress because of the IAT needing fixups. If your process calls out to a function in a module which is not loaded in the target process, this will likely crash the target process unless you explicitly load the required module first. For example, if your payload/host process uses USER32.dll but the target process has not loaded this module, calling MessageBoxA may crash the target process since there's wrong bytes or no memory allocated at the expected address.