Docker and Kali Linux

Docker helps developers build, share, run, and verify applications anywhere with containers. More info on containers here.

A container is a standard unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another.

A Docker container image is a lightweight, standalone, executable package of software that includes everything needed to run an application: code, runtime, system tools, system libraries and settings.

My notes on Docker can be found here.

Introduction

This will be a guide on setting up Kali Linux in a docker container. Including pulling a new image, setting it up with prefer tools, services, configs, and a GUI if we want. Then covering how to save the image to a file to use on other machines or upload to docker hub to share.

Using Kali Docker Images

Grab the latest rolling docker image with

sudo docker pull docker.io/kalilinux/kali-rolling

Followed by

sudo docker run -it kalilinux/kali-rolling

NOTE: all the images do not come with the “default” metapackage. You will need to run:

apt update && apt upgrade -y

Installing tools

It’s pretty simple and basic from here - run

apt install -y [tool-name]

Eg.

apt install -y nano bloodhound.py xrdp

To get file sharing setup between our container and host, we need to have a directory setup for that. On our host, we make a folder wherever we want. Create a quick file in that directory so we can verify the share is working after we run it.

Now when running our Kali image with these parameters:

sudo docker run -v /home/th4ntis/Docker/Share:/home/share -it kalilinux/kali-rolling

When in our container, if we go to the /home/share directory, we can see the file we created on our host in the Share directory we made.

Getting a Graphical User Interface(GUI)

Most the tools we run in Kali will be CLI based but sometimes we may need/want a GUI. To get a gui running we need to run

sudo docker run -it -p 13389:13389 kalilinux/kali-rolling

Then we install the XFCE desktop environment with

apt install -y kali-desktop-xfce xrdp

Since we chose port 13389 for our port to forward, we need to edit the xrdp config

nano /etc/xrdp/xrdp.ini

Change the line that says

port=3389

port=13389

Then start the xrdp service

service xrdp start

Verify the XRDP service is running

service xrdp status

Before we start the RDP session, we need to change the root password with

passwd

Adding a new non-root user

Some tools don't play wel when running as root, so we should make a new user. To do this, we run

adduser [user]

Type in the password, then you can press ENTER when asked for full name, room number, etc.

OPTIONAL: To add the new user to the sudoers file. This will make sure the new user can permissions with as a super user.

usermod -aG sudo [user]

We can change to the newly created user with

su [user]

Making a custom image

While in your container, install all your tools, setup configs, etc. It is important to keep the container running with all your settings, tools and configs! Exit the container and keep it running with

CTRL+P CTRL+Q

Then run

sudo docker commit [container_id] [image_name]

Save the container in an image you can transfer to other machines with

sudo docker save [image_name] > [image_name].tar

Now load the image on the new machine with

sudo docker image load < [container_name].tar

Now run the new container with all of our settings

sudo docker run -it -p 13389:13389 -v /home/[user]/Docker/Share:/home/share [container_name]

I've added that as an alias in my terminal

alias kali-docker='sudo docker run -it -p 13389:13389 -v /home/th4ntis/Docker/Share:/home/share [container_name]'

Conclusion

That’s it! Now you have a nice, custom Kali docker image setup with our tools, users, settings, and configs that don’t require any setup or even an internet connection!