It is relying on the fact that electronics emit an electromagnetic signal
The US Department of Defense is working on a classified project called the Tactical Electromagnetic Cyber Warfare Demonstrator program, which is aimed at giving the Army the ability to inject and extract data from network cables without any physical contact.They want to achieve this by leveraging the fact that electronics emit an electromagnetic signal. In theory, this signal could be intercepted and even tampered with by using radio frequencies.
According to Defense News, the DOD is hoping to be able to plant worms inside isolated networks from land vehicles or aircrafts. This would give a whole new meaning to the concept of cyber warfare.
On the other hand, this is not an easy task. Furthermore, as Bitdefender Senior E-Threat Analyst Bogdan Botezatu highlights, critical networks usually utilize coaxial cables, instead of Cat 5 or Cat 6 cables.
Coaxial cable has very low radiation losses and low susceptibility to external interference.