Securing Voice over IP in the Modern Network Era: Systematic Analysis of Weaknesses and a Framework for Holistic Protection

Voice over Internet Protocol (VoIP) has become a critical technology in modern communication networks, including enterprise, government, and public networks. With the ongoing shift from traditional Public Switched Telephone Network (PSTN) to IP-based systems, VoIP's security landscape has become more complex and challenging. This research paper aims to provide a systematic and detailed analysis of VoIP's weaknesses, offering a structured framework for strengthening VoIP security in diverse network deployments. The paper begins by examining the vulnerabilities present in VoIP protocols, including SIP and H.323. It then delves into common signalling attacks, media stream vulnerabilities, endpoint security issues, and network-based threats targeting VoIP systems. The limitations of traditional VoIP security measures are assessed, and a multi-layered security framework is proposed, encompassing network hardening, protocol security, encryption techniques, intrusion detection systems, behavioural analytics, and secure architectural principles. The paper synthesises global best practices, emerging attack trends, and deployment challenges to offer a comprehensive and adaptable framework for enhancing VoIP resilience in corporate and critical communication infrastructures. The research highlights the importance of unified VoIP security architectures that leverage threat intelligence, adaptive monitoring, and robust encryption to ensure the confidentiality, integrity, and availability of VoIP communication channels.