GE Grid Solutions’ Reason RT430 GNSS Precision-Time Clock is referenced to GPS and GLONASS satellites. Offering a complete solution, these clocks are the universal precision time synchronization units, with an extensive number of outputs which supports many timing protocols. including the DST rules frequently used on power systems applications. In accordance with IEEE 1588 Precision Time Protocol (PTP), the RT430 is capable of providing multiple IEDs synchronization with better than 100ns time accuracy over Ethernet networks. Despite being likely to never lose time synchronization from satellites, the RT430 GNSS features a TCXO as its standard internal oscillator ensuring free-running accuracy when clock is not locked. IOActive found that the RT430’s web application exposed several shell scripts that allowed authentication to be bypassed, leading to a full compromise of the device.