EXPERIMENTAL STUDY ON PROTOCOL VULNERABILITIES OF NON TERRESTRIAL NETWORKS

The integration of Non-Terrestrial Networks (NTN) into 5G extends global connectivity but introduces significant security vulnerabilities across both the physical and protocol layers. This thesis presents a practical multi-layer security assessment of a 5G NTN environment using a experimental testbed composed of OpenAirInterface, Software Defined Radios, and a PROPSIM channel emulator. The experimental campaign targeted two key domains. At the Physical Layer, smart jamming attacks were deployed against the Synchronization Signal Block (SSB). Results demonstrated that a custom-built Reactive Jammer could deny network access with superior energy efficiency and stealth compared to continuous Toggle Jamming. At the Core Network layer, a fuzzing campaign targeting NAS and NGAP protocols revealed the fragility of open-source implementations. Specifically, malformed packets frequently triggered critical Segmentation Faults in the Core, leading to immediate service denial. These findings confirm the SSB as a single point of failure and highlight serious stability issues in current open-source 5G stacks, emphasizing theurgent need for robust error handling strategies and cross-layer defense mechanisms in future satellite deployments.