Pwn2Win CTF 2020

About our NIZK (Non-Interactive Zero-Knowledge) Platform: arXiv:1708.05844.

Installing the platform client

Next year we plan to have a web-based client. For this edition, please choose one of the options below to install our command line client.

Option 1: Docker

Clone this repository:

git clone https://github.com/pwn2winctf/2020.git
cd 2020

Then either generate a new SSH key:

ssh-keygen -t ed25519 -f .ssh/id_ed25519
cat .ssh/id_ed25519.pub  # add to your GitHub account (https://github.com/settings/keys)

or copy an existing one:

cp ~/.ssh/id_* .ssh/

Finally, follow the registration instructions below, always replacing $CTF with ./dctf.

CTF=./dctf

Option 2: LXD

Create the container:

wget https://static.pwn2win.party/pwn2win2020.tar.gz
lxc image import pwn2win2020.tar.gz --alias=pwn2win
lxc launch pwn2win pwn2win
lxc exec pwn2win -- git pull   # make sure the repository is up to date

Then either generate a new SSH key:

lxc exec pwn2win -- ssh-keygen -t ed25519
lxc exec pwn2win -- cat .ssh/id_ed25519.pub  # add to your GitHub account (https://github.com/settings/keys)

or copy an existing one:

lxc file push ~/.ssh/id_* pwn2win/root/.ssh/

Finally, follow the registration instructions below, always replacing $CTF with lxc exec pwn2win -- ./ctf.

CTF="lxc exec pwn2win -- ./ctf"

Option 3: Your box

Make sure you already have an SSH key in your box which is linked to your GitHub account.

Clone this repository:

git clone [email protected]:pwn2winctf/2020.git
cd 2020

And install the dependencies, e.g. for Debian or Ubuntu:

sudo apt-get install libsodium23
curl https://bootstrap.pypa.io/get-pip.py | sudo -H python
sudo -H python -m pip install -r pip-requirements.txt

Finally, follow the registration instructions below, always replacing $CTF with ./ctf.

CTF=./ctf

Registration

Run:

$CTF init

If you are the leader of the team, answer y when you are asked whether you want to register a new team. Share the generated team-secrets.json file with the members of the team.

If you are one of the other members of the team, place the team-secrets.json file shared by your team leader in your 2020 directory.

Challenges

Challenges are available at https://pwn2.win/.

If you prefer to browse them locally, you may also run:

git pull && $CTF challs

Flag submission

If the challenge was recently released, you might need to update your local repository first:

git pull

To submit a flag:

$CTF submit --chall challenge-id 'CTF-BR{flag123}'

You may omit --chall challenge-id from the command, however it will be very slow to run this way since it tries the supplied flag against every challenge.

Scoreboard

You can see the scoreboard at the game URL (https://pwn2.win) or running the command:

$CTF score --names --pull

Support

You may reach us through #pwn2win at irc.freenode.net.