I created an incredibly blazing-fast note application!
Instancer:
nc dark-note.{int,dom}.seccon.games 1337
Note: The instancer has no bugs or vulnerabilities (at least in my intended solution).
Launch a challenge server:
cd build
docker compose up
Run the author's solver:
docker run -it \
-e SECCON_HOST=localhost \
-e SECCON_PORT=1337 \
-e ATTACK_BASE_URL=http://attacker.example.com \
-p 8080:8080 --network=host \
(docker build -q ./solver)
where http://attacker.example.com is an origin forwarded to http://localhost:8080.