Without the protection with SSL/TLS or IPSec, it will be easy for an attacker to capture the SIP signalling and RTP (Real-time Transport Protocol) traffic using tools like Wireshark.
National Security Agency | National Security Council | Organization for Security and Co-operation in Europe | United States National Security Council | United Nations Security Council | National Security Advisor | United States Department of Homeland Security | security | National Security Advisor (United States) | Social Security Administration | United Nations Security Council resolution | United Nations Security Council Resolution 1267 | Transportation Security Administration | Hacker (computer security) | George C. Marshall European Center for Security Studies | United Nations Security Council Resolution 1373 | Transport Layer Security | Social Security | Committee of General Security | United Nations Security Council Resolution | Social Security (United States) | High Representative of the Union for Foreign Affairs and Security Policy | computer security | National Security Archive | IMS | National Security Act of 1947 | Ministry of Public Security of the People's Republic of China | Internet security | hacker (computer security) | Farm Security Administration |