The disclosure generally relates method, system and apparatus to prevent denial of service (DOS) attacks on PCIe based computing devices. In an exemplary embodiment, an independent register is used in combination with a filter driver and additional logic to form an integrity check for power down instructions. An exemplary system includes a register circuitry corresponding to the IP device, the register circuitry having a designated storage bit to indicate an unlocked state of the register; a filter driver to receive a first power state transition request when the IP device is idle after a predetermined period, the power state transition request defining a timeout period; a controller to change the power state of the IP device to the unlock state; a decision logic to receive and authenticate a second power state transition request in response to validation of register circuitry being unlocked.