For a long time, attacks on radar systems were limited to military targets. With increasing interconnection, cyber attacks have nowadays become a serious complementary threat also affecting civil radar systems for aviation traffic control or maritime navigation. Hence, operators need to be enabled to detect and respond to cyber attacks and must be supported by defense capabilities. However, security research in this domain is only just beginning and is hampered by a lack of adequate test and development environments. In this demo, we thus present a maritime Radar Cyber Security Lab (RCSL) as a holistic framework to identify vulnerabilities of navigation radars and to support the development of defensive solutions. RCSL offers an offensive tool for attacking navigation radars and a defensive module leveraging network-based anomaly detection. In our demonstration, we will showcase the radars’ vulnerabilities in a simulative environment and demonstrate the benefit of an application-specific Intrusion Detection System.