Chapter 18 Troubleshooting : ­Verifying FortiGate admin access security : Disable auto installation via USB
  
Disable auto installation via USB
An attacker with a physical access to the device could load a new configuration or firmware on the FortiGate using the USB port, reinitializing the device through a power cut. To avoid this, execute the following CLI commands:
config system auto-install
set auto-install-config disable
set auto-install-image disable
end