THE THREAT HOW IT WORKS

Distributed Acoustic Sensing (DAS) is a commercially available technology that sends laser pulses through ordinary fiber and analyzes the reflected light for vibration. DAS is widely used for valuable applications, including protecting pipelines, utilities, borders and long-haul communications routes. In fact, NIS offers DAS-based solutions for infrastructure-protection applications through its FOCUS product lines. However, recent research has demonstrated that the same sensitivity can extend to nearby speech—allowing fiber to function as an optical microphone.

THIS IS NO LONGER THEORETICAL 

80%+ intelligibility
Reported under tested conditions in research presented at the 2026 NDSS Symposium.

50+ meters
Demonstrated distance between the attacker and target in the published research.

AI-assisted transcription
Recent reporting showed that faint fiber-borne signals could be converted into readable conversations.

Clear conversations recovered by NIS
NIS testing has independently confirmed that the threat has advanced beyond the garbled audio associated with earlier DAS technology.  Eavesdropping over Fiber (EoF) is not an emerging threat - it's already here.

How to identify a fiber being used for Eavesdropping? To use optical fiber as a microphone, an eavesdropper must connect an acoustic sensor to the fiber - and the light from that unauthorized sensor can be detected.  NIS has always believed that detection is the best defense for communications and infrastructure protection, and it is critical for eavesdropping defense as well.

INTRODUCING INLIGHTEN^TM

InLighten Detects When Dark Fiber Starts Listening. InLighten is NIS’s patented technology purpose-built to:

• Detects unauthorized sensing light on dark fiber
• Provides real-time warning of a potential EoF attempt
• Continuously monitors fiber that should remain inactive
• Reveals remote threats that may leave no physical device behind

You cannot stop a threat you cannot see.

InLighten raises the alarm when dark fiber starts listening.

END-TO-END SECURITY & COMPLIANCE

Detect EoF. Protect the Entire Network

InLighten detects attempts to use dark fiber for acoustic surveillance, while NIS’s non-acoustic sensing technologies protect classified communications infrastructure against tapping, tampering and physical attack.

INTERCEPTOR NX™ protects U.S. Government and classified networks without using acoustic-based sensing. The protection system cannot listen to conversations or become a surveillance tool itself.  Therefore, it is perfect inside a building or across a campus. 

Together, these technologies provide a layered approach:

• • • InLighten™ detects Eavesdropping over Fiber on unused fiber
    • INTERCEPTOR NX™ protects classified network infrastructure from physical intrusion and tampering
    • INSIGHT™ provides centralized alarm visibility, notification, and response management

DO YOU KNOW IF YOUR FIBER IS LISTENING?

Schedule a confidential briefing and demonstration to understand your potential exposure, see Eavesdropping over Fiber in action and learn how InLighten detects an attempted attack.