VoIP technology is Eight New Services among Ubiquitous-IT839 strategies. This paper tested wiretapping of VoIP service in connected a soft phone and LAN and WAN sections, Internet telephones and a device, IP PBX, a banner operator network to have been connected to VoIP Internet network. As a result of having experimented on wiretapping of VoIP networks, Vulnerability was found, and a wiretapping by attacks of a hacker was succeeded in a terminal and Proxy and attachment points of a VoIP network like a hub to follow a CVE list. Currently applied a security plan of an each wiretapping section in viewpoints of 6 security function of Access Control, Confidentiality, Authentication, Availability, Integrity, Non-repudiation in VoIP networks named to 070. Prevented wiretapping of contents by the results, the AES encryption that executed wiretapping experiment about a packet after application of a security plan. Prevented wiretapping, and kept security and audit log, and were able to accomplish VoIP information protection to network monitoring and audit log by an access interception and qualification and message hash functions and use of an incoming refusal.