Technical aspects of CTF contest organization

This article outlines CERT Polska’s approach to running CTF competitions at scale, covering containerized task delivery with Docker/Compose and systemd, sandboxing risky pwn services via nsjail, implementing Selenium/xvfb-based admin bots for web challenges, fronting services with nginx for TLS termination and IP-hash load balancing, automating end-to-end health checks and service monitoring in Icinga2 with Mattermost alerts, and enabling rapid failover and reproducible deployments using Ansible.