CISA is aware of a public report of insecure implementation of CAN bus networks affecting aircraft. According to this report, the CAN bus networks are exploitable when an attacker has unsupervised physical access to the aircraft. CISA is issuing this alert to provide early notice of the report.
An attacker with physical access to the aircraft could attach a device to an avionics CAN bus that could be used to inject false data, resulting in incorrect readings in avionic equipment. The researchers have outlined that engine telemetry readings, compass and attitude data, altitude, airspeeds, and angle of attack could all be manipulated to provide false measurements to the pilot. The researchers have further outlined that a pilot relying on instrument readings would be unable to distinguish between false and legitimate readings, which could result in loss of control of the affected aircraft.
CISA recommends aircraft owners restrict access to planes to the best of their abilities. Manufacturers of aircraft should review implementation of CAN bus networks to compensate for the physical attack vector. The automotive industry has made advancements in implementing safeguards that hinder similar physical attacks to CAN bus systems. Safeguards such as CAN bus-specific filtering, whitelisting, and segregation should also be evaluated by aircraft manufacturers.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on us-cert.gov. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage on us-cert.gov in the Technical Information Paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.