Control System Cyber Security
Discussion
One of the primary differences between IT cyber security and control cyber security is the latter ’ s need to protect life , physical property and the environment . Level 0 , 1 sensors are like the feelings in fingers and toes . They provide stimuli to the brain , which is the control system . If the sensing inputs to the brain are impaired for any reason , the brain ’ s actions will be incorrect . For example , if fingers are insensitive to a nearby flame , the brain will not react to pull fingers away . In the physical world , sensors measure pressure level , flow , temperature , voltage , current , strain , color , humidity , vibration , volume , chemistry , etc . These measurements are input to control systems such as PLCs , electrical breakers , motors , etc ., which are programmed to maintain systems within physical constraints based on appropriate sensor readings . These readings are assumed to be uncompromised , stable , and accurate . However , manipulation of these devices by cyberattack , hardware back doors or insider or physical manipulation , whether unintentionally or maliciously , can have catastrophic consequences .
The February 2017 NASA Inspector General ’ s report provided three case histories where IT technologies caused impacts or damage to control systems and operations . They illustrate the types of issues that can occur at a micro or macro scale .
• A large engineering oven that uses OT networks to monitor and regulate its temperature lost this ability when a connected computer was rebooted after application of a security patch update intended for standard IT systems . The reboot caused the control software to stop running , which resulted in the oven temperature rising and a fire that destroyed spacecraft hardware inside the oven . The reboot also impeded alarm activation , leaving the fire undetected for 3.5 hours before it was discovered by an employee .
• Vulnerability scanning used to identify software flaws that can be exploited by an attacker caused equipment to fail and loss of communication with an Earth science spacecraft during an orbital pass . As a result , the pass was rendered unusable and data could not be collected until the next orbital pass .
• Disabling of a chilled water Heating , Ventilation , and Air Conditioning ( HVAC ) system supporting a data center caused temperatures to rise 50 degrees in a matter of minutes , forcing shutdown to prevent damage to critical IT equipment .
Table 1 presents operational differences between IT and industrial control systems . These differences are compounded by how IT networking professionals and control system engineers approach the security issues in their purview . In many respects , they are fundamentally different ( Table 2 ). Issues such as Zero
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