ICT-enabled smart grid devices, potentially introduce new cyber vulnerabilities that weaken the resilience of the electric grid. Using real and simulated PV inverters, this work demonstrates how cyber-attacks on IEC 61850 communications to field devices can force an unstable state, causing voltage oscillations or overvoltage situations in a distribution grid. An automated resilience mechanism is therefore presented, combining intrusion detection and decentralised resilient controllers, which is demonstrated to assure stable operation of an energy system by counteracting cyber-attacks targeting embedded PV inverters.