Microcontroller fault injection method and system

An objective of the present invention is to carry out a temporary fault injection into existing hardware using only software and without changing the implementation of the existing hardware. A fault injection interrupt process into the operation of a CPU is commenced using an interrupt which the software does not use, and the interior state of the hardware is updated to the same value as the result if a fault occurred during the interrupt process. The CPU clock is accelerated and adjusted during the interrupt process such that the interrupt process time is less than or equal to the time required for the injected fault to have effect.