A method for protecting a mobile terminal device from cyber security threats that tests at least one electrical utility device, with the mobile terminal device having an internal firewall and having one or more network interfaces, with at least one w selected network interface and the remaining network interfaces disabled, and one or more electrical utility device physical interfaces, with at least one selected physical interface and the remaining unselected physical interfaces disabled, the method comprising: executing, by at least a processor in the mobile terminal device, test routines program codes stored in a non-transitory memory to configure the mobile terminal device to perform testing on at least one electrical utility device; testing the at least one electrical utility device using the mobile terminal device; prior to testing the at least one electrical utility device using the mobile terminal device, switching the mobile terminal device to a state where the internal firewall of the mobile terminal device is disabled; upon detecting the completion of the testing on the at least one electrical utility device, switching the mobile terminal device from a test state to a network state by performing the following steps within the mobile terminal device: disabling communication to the one or both of the selected physical interface and the network interface; enabling the internal firewall of the mobile terminal device, such that new communications or connections are permitted; selecting at least one network interface from among the disabled one or more remaining network interfaces to enable new communications, while keeping unselected one or more remaining network interfaces and the one or more remaining unselected physical interfaces disabled. executing, by at least a processor in the mobile terminal device, test routines program codes stored in a non-transitory memory to configure the mobile terminal device to perform testing on at least one electrical utility device; testing the at least one electrical utility device using the mobile terminal device; prior to testing the at least one electrical utility device using the mobile terminal device, switching the mobile terminal device to a state where the internal firewall of the mobile terminal device is disabled; upon detecting the completion of the testing on the at least one electrical utility device, switching the mobile terminal device from a test state to a network state by performing the following steps within the mobile terminal device: disabling communication to the one or both of the selected physical interface and the network interface; enabling the internal firewall of the mobile terminal device, such that new communications or connections are permitted; selecting at least one network interface from among the disabled one or more remaining network interfaces to enable new communications, while keeping unselected one or more remaining network interfaces and the one or more remaining unselected physical interfaces disabled. disabling communication to the one or both of the selected physical interface and the network interface; enabling the internal firewall of the mobile terminal device, such that new communications or connections are permitted; selecting at least one network interface from among the disabled one or more remaining network interfaces to enable new communications, while keeping unselected one or more remaining network interfaces and the one or more remaining unselected physical interfaces disabled.