x64 ELF code injector

A simple ELF code injector for x64. Uses segment padding to infect a file and will run the code on binary startup. For educational purposes only!

Getting Started

These instructions will set up all prerequisites to use the ELF injector.

Prerequisites

The program relies on gcc and objdump. The following command installs these on Ubuntu:

sudo apt-get install gcc binutils

Building

Simply cd into this directory and type:

make

Usage

The following command takes a assembly file and outputs a the dumped code section as file:

./create_injectable_file.sh input output

The injector has to be used as follows:

Usage:
        -I/-i input_file  : the file used as input
        -O/-o output_file : the file to infect
        -C/-c input_file  : the raw binary with the code to inject

Example

As an example, the injected_asm.S file can be used. Type:

./create_injectable_file.sh injected_asm.S inject
./elfinjector -i /bin/nc -o /home/user/bin/nc -c inject -P
./nc

This example will infect the /bin/nc file and print the letter "I" at startup of the binary. The output file can be found in /home/user/bin/nc.