Code Injection - Inserting A MessageBox

Ok, here comes the tut about injecting code. We will insert a MessageBox at program start like a little "nagbox". We will use my little example program in the zip file so I can better explain what we do. Note: it's important that our target program import the MessageBoxA function! That makes sense cause without it we can't use it. In this case we have to import it by hand which I will discuss in another tutorial. So check with Wdasm, PEditor, my Import Table Viewer or any other tool that MessageBoxA function is imported.