Deploying Axis: An Elixir Phoenix App in a CTF Environment

In this article, Vito shares insights from deploying Axis, a challenge app built with Elixir Phoenix, during the DEF CON Capture the Flag finals. The app featured a critical flaw (CWE-94) and was a learning experience amidst technical obstacles. Vito details the intricacies involved in using EPMD (Erlang Port Mapper Daemon) for connecting Erlang nodes and managing challenges like Docker's compatibility with different architectures. The deployment process was fraught with difficulty, particularly due to issues with Puppeteer and network configurations. Through persistence and troubleshooting, the right setup was achieved, allowing Axis to participate in the event successfully. The article ultimately serves both as a technical guide and a reflection on Vito's journey in the context of competitive hacking challenges.