IPhone – iOS MAC address randomization for personal hotspots

iphonemac addressNetworkscanningwifi

On my friend's iPhone (not sure which one but presumably a recent version) when she creates a personal hotspot, there's a program running on her computer that scans all WLAN networks around it and it logs the SSID and BSSID (MAC address) for all networks it detects.

The thing is the scanner logs a different MAC address for the hotspot every time she stops and re-starts the personal hotspot. I've read about iOS randomizing MAC address when the phone is scanning for networks.

Does that meant that the MAC address of the iPhone's personal hotspot will also show up different to a third party app running on a different machine, scanning for local WLAN networks every time the iPhone hotspot is stopped and restarted?

Best Answer

Since iOS 8, Apple has implemented MAC address randomization as a security measure against tracking. It will will generate a random MAC address when

  • responding to a probe request (another node is scanning)
  • sending a probe request (the iDevice is scanning)

However, when joined, it will use it’s own real MAC address.

Basically, users can be tracked when the iPhone responds to a management packet that’s broadcast. The device (not limited to iPhones/iPads) will respond back with a response packet that includes the MAC address of the device. Companies will log this device when it responds and track your movements. Apple, randomizes the MAC address so that what that entity logs is mostly useless. It’s important to note that this isn’t limited to the hotspot function of the iOS device, but to all scanning requests.