Container-based technologies have become widespread today. Docker is one of them. Each Docker container is self-contained and serves a single purpose. Docker-based virtualization has gained a lot of momentum in the cybersecurity field. It is commonly used to develop distributed security systems, virtual environments for training purposes, intentionally vulnerable honeypots deployed in the network to divert attackers. Docker can also be effectively used to train penetration testers, i.e., security professionals who mimic hackers’ actions by attempting to break into a target system with the aim of finding critical vulnerabilities before real attackers can exploit them. Several works have adopted container-based virtualization to realize frameworks for penetration testing. Though, there is no fullyfledged hacking toolset based on Docker. In this work, we present HOUDINI (Hundreds of Offensive and Useful Docker Images for Network Intrusion), a publicly available and easy-to-use open source platform that can be used to support security testing with Docker containers. We define quality criteria that must be met for an image to be included inside HOUDINI and benchmark our own images against alternative ones that are publicly available. Finally, we show the effectiveness of using container-based virtualization by simulating a complete hacking session with Docker.