Acoustic Leakage

After every TSCM inspection, as you would expect we produce a detailed report for the client describing what we have done, findings and recommendations etc. Interestingly, numerous clients have recently commented on several of the additional areas we cover when conducting a sweep, none of which they were aware of and came as a pleasant surprise. Clearly when conducting the inspection the device sweep, and telephone-line checks are priority to ensure no eavesdropping devices are present. However, clients appreciate the additional checks carried during the inspection. A recent example was following a sweep, a client commented on our report findings where we had identified a significant risk, and they welcomed us highlighting the issue and the recommendation on remediation to solve the problem. The issue was ‘acoustic-leakage’ in virtually all their meeting/conference rooms.

Acoustic (sound) leakage is the oldest form of eavesdropping (‘listening through walls’). Sometimes the acoustical leakage is free & clear; an open discussion in a public area, like a restaurant or train. Reportedly, in the US a financial dealmaker blew a $15 billion takeover by discussing the details on a train. He didn’t realise a rival was sitting within earshot. Unfortunately incidents like this do happen – the best advice to avoid this type of incident is clearly to keep your conversations confidential. Acoustical leakage often occurs even when specific steps are taken to keep conversations private, like closing an office or conference room door. But, as sure as sound wants to migrate, outsiders want to hear, and poor sound proofing will assist someone listening in or recording a conversation.

When offices are designed, in general, it’s about maximising space, fitting it with the relevant technology and decorating with the corporate branding – it’s unlikely that acoustics are considered. In the recent example, the acoustic-leakage was significant. This poses a threat, especially if there is a disgruntled employee/malicious insider or even if a 3rd party within the vicinity is meeting in another room. The voice travels quite easily, and you could easily hear the conversation. We were going utilise the ‘Andre’ to test the acoustic leakage by using the microphone on the glass pane; however, it wasn’t needed as even without the Mic, everything could be heard by a simple physical voice check.

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