Acoustic Eavesdropping with Telecom Fiber Optic Cables (ndss-symposium.org)

• Fiber cables act as unintended acoustic sensors
• Phase-shift analysis converts light into audio
• Threat to secure facilities and critical infrastructure

"Telecommunication fiber optic cables are increasingly vulnerable to acoustic eavesdropping, where standard fiber is repurposed as a remote microphone. By analyzing minute phase shifts in laser light caused by sound-induced mechanical vibrations, actors can reconstruct audio from environments adjacent to cable conduits. This technique bypasses traditional encryption as it intercepts the physical medium's reaction to sound rather than the transmitted data itself. The threat poses a strategic risk to critical infrastructure and secure facilities where high-density fiber bundles are physically close to sensitive areas. Mitigations require enhanced physical route hardening, acoustic dampening in conduit systems, and a re-evaluation of current network infrastructure security models to counter passive, non-intrusive surveillance techniques."