Library Guide

Mails used to be the easiest way to spread malware. So obviously Gmail doesnt allow users to attach windows executables (.exe) to mails in order to protect its users from screwing up their windows machines. However, we may have to send .exe files which are not malware via mail. Before, you couldve just renamed the extension from .exe to something else or made a zip/rar archive and gmail would simply allow you to attach it. Sadly, it doesnt work anymore as gmail started reading file headers of attachments and started reading files inside zip/rar archives.

So I figured out a simple way to do this using steganography. The idea here is to embed the exe file inside any image and attach it to the mail. Gmail will think that it is just an image and will be oblivious to the fact that there is an exe file hidden inside that. Later the other user can simply extract the exe file from the image and use it .

Usage

Download mailexe (Dont forget to make it executable).

Sending

$ ./mailexe -e  [exe file] [image file]

A file called image.png will be created. This image file has exe file hidden in it. Send this via gmail.

Receiving

How it works?

Sending

Step1

Convert the image and the executable to base64 and save it in a file

$ base64 [image file] > temp
$ base64 [exe file] >> temp

Step2

Decode base64 file and save it as image

$ base64 -d temp > image.png

Step3

Send image.png and the original image file via gmail

Receiving

Step 1 

Step2