N0vajay05

You really need to run these camera's behind a VPN and not forwarding a port. It's very easy to find common cameras that are exposed to the internet and utilize known vulnerabilities to get to them. Put the NVR behind a VPN and they will be good to go. You can go with something like pfSense as your router, use a raspberry pi to create an OpenVPN server connection, or to go simple, use a TP-Link AC2300 router with built in OpenVPN server.