Covert surveillance devices: Audio

An adversary can install microphones anywhere within range of where conversations might occur — a living room, a car dashboard, a regular outdoor meeting place, etc. They can be very sensitive and successfully pick up conversations even when there is loud music playing in the background or people are whispering.

Covert microphones can be extremely small — just a few millimeters — especially if they record locally (e.g. on an SD card) and do not transmit their recordings.

Recorded conversations can be used as evidence in court if incriminating matters are discussed, or if they can be misconstrued to appear incriminating in the eyes of a judge. Non-incriminating, mundane conversations can reveal a great deal about the targets of surveillance and help in network mapping.

See Ears and Eyes and the hidden devices topic.

Used in tactics: Incrimination

Mitigations

NameDescription
Bug search

With the proper techniques and tools, you can locate hidden microphones, and eventually remove them.

Outdoor and device-free conversations

To avoid being picked up by hidden microphones, sensitive conversations should not take place indoors, in cars, or at habitual outdoor locations.

Physical intrusion detection

Installing hidden microphones in a space often requires an adversary to covertly enter the space. With proper preparation, you can detect such a covert entry.

Used in repressive operations

NameDescription
Renata

Six hidden microphones and a camera were found in a house after the operation[1]. The microphones were found in the living room, hallway, and bedrooms. The camera was found in the intercom system.

See the corresponding Ears and Eyes case.

Scintilla

A microphone hidden in a squat for two and a half years recorded conversations that were used by the investigators to prove that the accused comrades knew each other, talked together regularly, worried about the creation of a DNA database and the impossibility of resisting DNA collection, discussed writing a text to be published[2].

See the corresponding Ears and Eyes case.