Newly adopted VoLTE requires changes in all associated parties, such as 3GPP standard, device, operating system, and cellular core networks. Therefore, it is not too surprising that it has security problems. However, it turns out that it has way too many problems. In this talk, we introduce how you can freely send data in the cellular network, and how an attacker can perform caller spoofing and denial of service attacks on calls to disable the target’s calling. Furthermore, we explain how small implementation glitch on VoLTE may lead to break the whole cellular network down.