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Cyber Security

Secure Bluetooth Pairing

TL;DR

Bluetooth pairing can be a security risk if not done carefully. This guide shows you how to pair devices safely, reduce visibility, and spot potential problems.

1. Understand the Risks

When Bluetooth is enabled, your device broadcasts its presence. Attackers can try to intercept the pairing process or connect without permission. Common risks include:

  • Man-in-the-Middle Attacks: Someone intercepts communication during pairing.
  • Bluejacking: Sending unwanted messages (less harmful, but annoying).
  • Bluesnarfing: Accessing data from your device without permission.
  • Pairing Exploits: Vulnerabilities in the pairing process itself.

2. Pairing Mode – Keep it Short!

The longer your device is discoverable, the greater the risk. Only put your device into pairing mode when you are actively trying to connect a new device.

  • Android: Go to Settings > Connections > Bluetooth. Tap ‘Scan’ or similar to start searching. The pairing window usually times out automatically after a few minutes.
  • iOS (iPhone/iPad): Go to Settings > Bluetooth. Your device is discoverable for a short period when you’re actively setting up a new connection.
  • Windows: Go to Settings > Devices > Bluetooth & other devices. Ensure ‘Show notifications to connect using Swift Pair’ is disabled if not needed. Click ‘Add Bluetooth or other device’.

3. Verify the Pairing Code

Most devices display a pairing code (a number) during connection. Crucially, confirm this code on both devices!

  • If the codes don’t match, cancel the pairing immediately. This is a strong sign of an attack.

4. Limit Bluetooth Visibility

Reduce the time your device broadcasts its presence.

  • Android: After pairing, Android usually keeps devices visible for a limited time. Check app permissions to ensure only trusted apps can access Bluetooth.
  • iOS: iOS automatically stops broadcasting when not actively pairing.
  • Windows: Turn off Bluetooth completely when not in use. Go to Settings > Devices > Bluetooth & other devices and toggle the switch to ‘Off’.

5. Remove Unused Paired Devices

Regularly clear out old pairings you no longer need.

  • Android: Settings > Connections > Bluetooth. Tap the settings icon next to a paired device and select ‘Unpair’.
  • iOS: Settings > Bluetooth. Tap the ‘i’ icon next to a device and select ‘Forget This Device’.
  • Windows: Settings > Devices > Bluetooth & other devices. Select the device and click ‘Remove device’.

6. Be Careful with Public Places

Avoid pairing new devices in public areas where attackers might be present.

  • Disable Bluetooth if you don’t need it while out and about.

7. Keep Your Software Updated

Software updates often include security patches that address vulnerabilities in the Bluetooth stack.

  • Ensure your operating system (Android, iOS, Windows) is up to date.
  • Update firmware on your Bluetooth devices if possible (check manufacturer’s website).

8. Check for Suspicious Activity

Monitor your device for unusual behaviour after pairing a new device.

  • Unexpected data usage.
  • Unexplained battery drain.
  • Strange notifications or app activity.
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