A method and system for protecting a printed circuit board (PCB) from tampering positions a physical sensor proximal to the PCB. An initialization period is established and an output signal from the sensor is continuously monitored to establish threshold parameter data. Periodically, the sensor is polled and an output signal received which is compared to the threshold parameter data. A detected intrusion signal is generated if the received signal exceeds the threshold by a predetermined level. A detected intrusion is validated using a sent of validation rules which analyze the detected intrusion based on historical sensor output values and factors such as duration or frequency of intrusion detections. If the detected intrusion is validated, a validated signal is generated which triggers a reset processor to output a reset signal that causes erasure of at least a portion of onboard memory.