Implement network segregation depending on the sensibility and purpose of each network. Isolate, whenever possible, critical infrastructure network segments. Include ‘traditional’ perimeter safeguards (e.g. firewalls, antivirus or IDS/IPS). Systems under maintenance should be disconnected from the rest of the system. Only use dedicated systems and computers to carry out the updates. Remote access must only be enabled for the duration of the purpose it was enabled for, and only used by internal personnel (or with the supervision of internal personnel). Carry out periodic risk analysis. Implement configuration management in order to secure your system. Log monitoring to detect anomalous or unexpected connections and/or traffic.