Infecting an exe file

Hello viewer,

Today i will be blogging something more interesting, but not for the casual..
I decided to try to learn more about malware, since i already know loads about game "mods" and techniques (just theory) i might aswell try something myself.

I will be posting a guide/tutorial/whateveritwillbecome on writing a program that injects something, or possibly part of its own code into an executable, neato eh?


First of all lets start with the information i know, an exe file contains a header with important information, and mapable sections (people who have dabbled with reverse engineering know what i mean :-D)
my initial goal is to modify the EP (entry point) to point to my "evil" code, wich will return to the real origin after its done being evil.



after some quick googling i found a nice picture displaying the exe format in a simplistic way, the PE address is located in the Optional header (aka PE header) and is a RVA (relative virtual adress) so this needs to be converted to a usable address.

after our program has has collected the necasary data, we can begin to infect the file, i will be either searching for some unused space or somehow create my own, i am not sure of this but im sure that this will be resolved when im at the stage of writing the code :).



 This blog is just a bit of preperation on my side, i will be writing actual code soon when i feel like.

Hope i wasnt too technical.