Physical hacking of airplane electrical systems is a realistic possibility that could bring down aircraft, the Department of Homeland Security warned Tuesday.
The government said researchers at a cybersecurity firm identified ways an attacker could cause aircraft displays to show false "engine telemetry readings, compass and attitude data, altitude, airspeeds, and angle of attack."
"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," wrote the Cybersecurity and Infrastructure Security Agency, which is part of DHS.
Rapid7, the research firm, said it investigated the risks with small aircraft rather than larger commercial planes.
Hackers must have physical access to the aircraft, the company said. The attack involves physically plugging a malicious device into the electronics systems that increasingly control the displays and functions of modern aircraft.
Similar -- but more secure -- technology is used in cars. The Rapid7 researchers attributed that difference to the fact that "even small, personal aircraft are rarely parked in unmonitored, open areas like open parking lots or public streets," as is the case for cars.
The DHS notice recommended that "aircraft owners restrict access to planes to the best of their abilities" and that manufacturers review the security of their electronic systems, and consider using protections similar to those used in cars.
Neither the company nor DHS identified specific aircraft or manufacturers.