Voice over Internet Protocol (VoIP) is a widely deployed service since the commencement of voice and data integration. This was done in a bid to reduce cost and management concerns. VoIP uses the same infrastructure as traditional data networks and thus, inherits all the security challenges of a data network. In addition, VoIP exhibit self-inflected problems resulting from network components and the protocol adopted. This paper present the security threats witnessed in VoIP telecommunication. The paper discusses the security threats in tandem with confidentiality, integrity and availability principle. Examples of security issues under consideration include; spamming, identity spoofing, call tempering, DoS, and Man-in-the-middle attacks among others. Finally, the paper will outline the common countermeasures adopted to mitigate the threats.

Keywords: VoIP, VoIP security, voice over IP security, DoS, spamming, identity spoofing, call tempering, Cybercrime, Computer security