Outdoor and device-free conversations is the practice of conducting sensitive or incriminating conversations outdoors and without electronic devices, to ensure that they are not overheard by an adversary.
Outdoor and device-free conversations are necessary because:
- Indoor spaces, including cars can contain covert surveillance devices.
- Electronic devices can be infected with malware that can turn them into covert microphones.
Outdoor conversations can be recorded with covert microphones or long-range parabolic microphones during a physical surveillance operation (with ranges of up to 300 meters). For example, in Italy in 2019 a microphone was hidden in a fake stone in front of a prison where gatherings were often held. For this reason, you should conduct outdoor conversations while walking, or for larger group conversations where it would be difficult to move, conduct them in spaces that change regularly and are difficult to place under audio surveillance.
During device-free conversations, you should not turn off your phone, remove its batteries, or place it in a Faraday bag, as this generates metadata about who is having sensitive conversations, when, and where. Instead, leave your phone at home. Also, a Faraday bag does not prevent audio from being captured, only from being transmitted, which could happen when the phone later reconnects to the network.
See the “Security culture” topic.
Techniques addressed by this mitigation
| Name | Description | |
|---|---|---|
| Covert surveillance devices | ||
| Audio | You can conduct sensitive conversations outdoors and without electronic devices to prevent an adversary from recording those conversations with covert audio surveillance devices. | |
| Mass surveillance | ||
| Video surveillance | You can conduct sensitive conversations away from surveillance cameras to prevent an adversary from recording those conversations with surveillance cameras equipped with microphones. | |