Advances in fifth-generation (5G) networks enable unprecedented reliability, speed, and connectivity compared to previous mobile networks. These advancements can revolutionize various sectors by supporting applications requiring real-time data processing. However, the rapid deployment and integration of 5G networks bring security concerns that must be addressed to operate these infrastructures safely. This paper reviews penetration testing approaches for identifying security vulnerabilities in 5G networks. Penetration testing is an ethical hacking technique used to simulate a network's security posture in the event of cyberattacks. This review highlights the capabilities, advantages, and limitations of recent 5G-targeting security tools for penetration testing. It examines ways adversaries exploit vulnerabilities in 5G networks, covering tactics and strategies targeted at 5G features. A key topic explored is the comparison of penetration testing methods for 5G and earlier generations. The article delves into the unique characteristics of 5G, including massive MIMO, edge computing, and network slicing, and how these aspects require new penetration testing methods. Understanding these differences helps develop more effective security solutions tailored to 5G networks. Our research also indicates that 5G penetration testing should use a multithreaded approach for addressing current security challenges. Furthermore, this paper includes case studies illustrating practical challenges and limitations in real-world applications of penetration testing in 5G networks. A comparative analysis of penetration testing tools for 5G networks highlights their effectiveness in mitigating vulnerabilities, emphasizing the need for advanced security measures against evolving cyber threats in 5G deployment.