[Analysis] PE Structure - Make the smallest executable

PE Structure

Make the smallest executable

Recently I faced a problem in my devs. I needed an executable that does nothing, but the smallest possible (to include it in a shellcode).

Here's the C++ code:

#include windows.h
int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
 return 0;
}

Nothing complicated.
I followed this tutorial to reduce the size of the PE : http://thelegendofrandom.com/blog/archives/2231

And it led to a tiny PE (1 ko). But not enough for me. 
Then I followed this tutorial :  http://win32assembly.programminghorizon.com/pe-tut1.html
and took this reference poster :  http://www.openrce.org/reference_library/files/reference/PE%20Format.pdf 
Updated here: http://blog.dkbza.org/2012/08/pe-file-format-graphs.html

I removed lots of null bytes, and modified the parameters to adjust both size and section offset. To finish, I loaded the PE into OllyDbg and modified the Entry point (which was not at the good place).

My PE is now 500 bytes, and fully functional.
Here's a schematic of the final PE structure. It can help to understand how a PE is structured.

REFERENCES

http://win32assembly.programminghorizon.com/pe-tut1.html
http://thelegendofrandom.com/blog/archives/2231 
http://www.openrce.org/reference_library/files/reference/PE%20Format.pdf 
http://blog.dkbza.org/2012/08/pe-file-format-graphs.html