
Cyber-Physical System Controls ◾ 45
attack on sensor X7 leads to an increase in pressure, as seen through sensor X5. However, this does
not lead to pressure beyond the safety limitations and the system recovers afterward.
An integrity attack on sensor X5, however, led to increases in pressure beyond the safety limit.
By enforcing the minimum value of the sensor, the purge valve was disabled to allow the pressure
to increase. Given the slow effects (slow dynamics) of the system, it is likely that human operators
would be able to notice and minimize damage by such an attack.
Examination of the effects of a DoS attack on the same sensor showed that ...