Using WiFi connection probe requests to track users

Probe requests are sent by mobile devices in order to obtain information about nearby Wi-Fi networks and to establish a Wi-Fi connection. When an access point receives a probe request, it responds with a probe response, creating a link between the two devices.

However, depending on the device’s age and operating system, probe requests may contain identifying information about the device’s owner. A request could, for example, include a preferred network list (PNL), which contains networks identifiable by their Service Set Identifier (SSIDs). According to experts, 23% of probe requests include SSIDs from previous networks to which the devices were connected. Read More…