Apps

Beware of the Flipper Zero Bluetooth spam attacks

2023-10-26 By admin

As we previously covered, Flipper Zero is a portable, open-source multi-tool device for pentesters and geeks. It can be used to interact with a variety of electronic devices, including RFID tags, radio remotes, iButton, and digital access keys but recently it has come back to the talk with a worrying feature.

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A custom Flipper Zero firmware called “Xtreme” has added a new feature to perform Bluetooth spam attacks on Android and Windows devices.

This feature, called “BLE Spam,” allows users to send a variety of spam messages to nearby devices, including phishing links, malware, and even denial-of-service attacks.

Android and Windows users are the target of Flipper Zero Bluetooth spam attacks – Image courtesy of Flipper Zero

How does Flipper Zero Bluetooth spam attack work?

Flipper Zero Bluetooth spam works by spoofing advertising packets and transmitting them to devices in range. Advertising packets are small packets of data that Bluetooth devices use to announce their presence and capabilities to other devices. By spoofing these packets, Flipper Zero can make it appear to other devices as if it is a legitimate Bluetooth device, such as a smartphone or wearable.

Once Flipper Zero has connected to a device, it can send it a variety of spam messages, including connection requests, pop-up notifications, and even malware. These messages can be customized to display any text or image, and they can be sent in a continuous loop to flood the device with notifications.

The full action? Well,

  1. Flipper Zero generates a random Bluetooth address
  2. It creates an advertising packet with the following information:
    • The random Bluetooth address
    • A service UUID that identifies the type of device Flipper Zero is impersonating
    • A custom advertising payload that can be used to display any text or image
  3. Flipper Zero transmits the advertising packet to all Bluetooth devices in range

When a Bluetooth device receives the advertising packet, it will see the random Bluetooth address and the service UUID, and it will assume that Flipper Zero is a legitimate device.

Once the device is connected to Flipper Zero, Flipper Zero can send it a variety of spam messages. These messages can be sent in a continuous loop to flood the device with notifications.

Flipper Zero Bluetooth spam attack
Flipper Zero Bluetooth spam attack works by creating a new UUID each time sending a message – Image courtesy of Flipper Zero

How do you protect yourself from Flipper Zero Bluetooth spam?

Flipper Zero Bluetooth spam attacks are a relatively new threat, but there are a few things you can do to protect yourself.

Disabling notifications for Bluetooth connection requests is the most effective way you can take. By disabling notifications, you will prevent your device from displaying pop-ups when Flipper Zero tries to connect to it.

To disable notifications for Bluetooth connection requests on Android:

  1. Go to Settings > Google > Nearby Share
  2. Turn off the toggle for Show notification

To disable notifications for Bluetooth connection requests on Windows:

  1. Go to Settings > Bluetooth & devices
  2. Click on Devices
  3. Scroll down to Device settings
  4. Turn off the toggle for Show notifications to connect using Swift Pair

There are also a number of third-party Bluetooth spam blocker apps available for Android and Windows devices. These apps can help to filter out spam messages and prevent them from reaching your device.

Featured image credit: Flipper Zero.

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