Security aspects of SIP based VoIP networks: A survey

Voice over Internet Protocol (VoIP) has become a very popular technology as it allows the users to make phone calls over the public internet. Some of its predominant features such as efficiency, cost-effectiveness and long distance communication made VoIP to stand apart from the traditional Public Switched Telephone Networks (PSTN). Session Initiation Protocol (SIP) is the contemporary signaling protocol used in VoIP Networks. The protocol itself is vulnerable to most of the threats that happen in VoIP Networks. Regardless to register highly scalable incidents, it is widely considered by experts as the futuristic target for attackers. This survey provides extensive and comprehensive analysis of various security threats faced by VoIP Networks. Also this paper exemplifies major defense mechanisms and their proposed techniques to combat the threats. Apart from that, this paper discusses open-source tools that can be simulated to conduct experiments. The main objective of this work is to motivate the researchers of VoIP domain to commence with novel defense techniques to overcome the threats.