In an ever-evolving digital landscape with cloud computing, mobility and IoT systems, more sophisticated approaches to vulnerability assessment are necessary. One of the central tools used in vulnerability testing is penetration testing, along with other techniques that are more broadly classified as ethical hacking. This discussion includes highlights from three case studies of ethical hacking in different settings. Highlights include approaches to ethical hacking and specific penetration techniques relevant to cloud computing and network security. Topics will also include challenges faced in ethical hacking within cybersecurity ecosystems and a discussion of a robust, integrative multi-layered used in ethical hacking.