Open interfaces in 5G Radio Access Network architecture facilitate flexibility, multi-vendor options, and agile development. Open RAN architecture utilizes open-source software (OSS) and proprietary products. The OSS enables numerous developers to participate in Open RAN technology and provides testing capabilities for interoperability and security assessment. Leveraging the openness of the software, developers can examine code flaws and identify overlooked vulnerabilities. To enhance the security of open-source software, particularly OpenAirInterface (OAI), we have conducted jamming and fuzzing attack tests for 5G private networks, focusing on Core and RAN networks. These threats were implemented on dedicated testbeds. The risk and impact of these threats have been elucidated to provide valuable insights into their prevention. In conclusion, our evaluations and findings will augment the technical capabilities of a resilient 5G system, encompassing reliability, availability, robustness, and security while safeguarding overall privacy.