Leaking Secrets from Air-Gap Computers by Spelling Radio Signals from RAM

RAMBO examines how malware on an air-gapped computer can transmit data despite the machine’s lack of network connections. Its central argument is that isolation from wired and wireless networks does not eliminate every communication channel: software can manipulate activity on the computer’s memory buses to produce radio-frequency emissions. The attacker can encode information into those signals, while a nearby receiver uses software-defined radio equipment and an ordinary antenna to capture them, recover the signal, and decode it into binary data.

The proposed channel can carry sensitive material - including files, images, keystrokes, biometric information, and encryption keys - at a reported rate of up to 1,000 bits per second. The work describes the attack’s design and implementation and reports evaluation results, presenting it as a practical out-of-band risk when malware has already compromised a supposedly isolated machine and a receiver is within range. It also proposes countermeasures intended to reduce this exposure. The key security implication is that an air gap blocks direct network access but cannot, by itself, guarantee that a compromised computer will not leak information through unintended electromagnetic emissions.