Systems and methods for protecting against cyber threats are disclosed. The system includes an external network accessing layer (ENAL) and a core computing asset overlaid by the ENAL. The ENAL comprises at least one external network access cell (ENAC), wherein the at least one ENAC contains at least one communications port, one or more processors, working and storage memories and is configured to be connectable to an external network and to inspect data received from the external network. The core computing asset is overlaid by the ENAL and comprises at least one core computer configured to not be connected to the external network but to be capable of being connected to the ENAL. The core computing asset contains data and software that are to be protected from cyber threat.