Abstract Ransomware-as-a-Service (RaaS) has evolved into one of the most significant cybersecurity challenges of the 2020s, transforming ransomware from isolated acts of digital extortion into a global, highly organized criminal industry. By mirroring the Software-as-a-Service (SaaS) model, RaaS enables even unskilled actors to deploy sophisticated ransomware through subscription- or profit-sharing arrangements. This paper explores how RaaS has industrialized cybercrime, expanding both scale and impact, and how enterprises, governments, and critical infrastructure operators can respond. Drawing from real-world case studies and the latest intelligence, it provides insight into the professionalization of ransomware and outlines best practices for mitigating its growing threat...