arjenz/ctf-proxy repository overview

⁠CTF setup in Docker

This setup is intended to create a quick working environment to play Capture The Flags (CTF), HackTheBox and similar.

⁠Setup

The easiest way to use this setup is to download docker-compose.yml and add the VPN config for the CTF; in this case, named ctf.ovpn. When those two are put in the same directory, run:

docker-compose up -d

⁠Download

You could simply download the docker-compose.yml using:

curl https://raw.githubusercontent.com/arjentz/ctf-docker/main/docker-compose.yml > docker-compose.yml

⁠Clone

Or you can clone the directory:

git clone https://github.com/arjentz/ctf-docker.git

To use the local containers, you need to change the following lines:

    image: arjenz/ctf-proxy

and:

    image: arjenz/ctf-kali

to:

    build: proxy

and:

    build: kali

respectively. Now you can edit the Dockerfiles and add packages as you please.

⁠VPN credentials

In case credentials are required with the VPN config, create a file called credentials.txt with the username and password each on one line, uncomment the following line in docker-compose.yml:

      - ./credentials.txt:/vpn/credentials.txt:ro

And, if required, add the following line to the VPN config:

auth-user-pass /vpn/credentials.txt

⁠Usage

You can use this setup in several ways.

⁠Command line

When all containers are running, enter the Kali container using:

docker exec -it ctf-kali tmux -CC

From this shell any commands needed to play the CTF can be run.

⁠Copy files

To copy a file to a volume, use:

docker cp $(pwd)/file.txt ctf-kali:/root/file.txt

⁠Browser

Challenges might involve a webpage, that is what the proxy container is used for. Run your browser through the proxy (with or without extra proxies) to let the traffic go through the VPN.

⁠X11 (on macOS)

To open an X11 application from inside the Kali container, first open XQuartz, and then run:

export DISPLAY=${hostname}:0 && xhost + ${hostname}

Now, it should be possible to open X11 applications. You can try it out with e.g. firefox or xtightvncviewer.

⁠Use filesystem

If you want to use the filesystem instead of a Docker volume, change the line:

    - ctf_kali:/root

to:

    - ./data:/root

When you start the containers, this will create a folder ./data in which the root directory of your Kali container will be mounted. You can now simply copy files to this folder in order to use them in your container.

⁠UID/GID (on Linux)

If using the filesystem on Linux, it is recommended to uncomment the following line in the docker-compose.yml:

    # user: '${UID}:${GID}'

And provide the environment variables when running the setup with:

UID=${UID} GID=${GID} docker-compose up -d

⁠Customise

Feel free to edit anything in any way. Mount other config files, add containers, anything. Suggestions can also be added to this repository.

⁠References

This setup makes use of dperson/openvpn-client⁠ and wernight/dante⁠.