An issue was discovered on KT MC01507L Z-Wave S0 devices. It occurs because HPKP is not implemented. The communication architecture is APP > Server > Controller (HUB) > Node (products which are controlled by HUB). The prerequisite is that the attacker is on the same network as the target HUB, and can use IP Changer to change destination IP addresses (of all packets whose destination IP address is Server) to a proxy-server IP address. This allows sniffing of cleartext between Server and Controller. The cleartext command data is transmitted to Controller using the proxy server's fake certificate, and it is able to control each Node of the HUB. Also, by operating HUB in Z-Wave Pairing Mode, it is possible to obtain the Z-Wave network key.