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ymsniper/whisper_bully

Analysis updated 2026-05-18

33PythonAudience · researcherComplexity · 4/5Setup · hard

TLDR

Whisper Bully is a Bluetooth research tool that extracts a device's real address, floods it offline, then hijacks the pairing bond during recovery.

Mindmap

mindmap
  root((Whisper Bully))
    What it does
      Bluetooth address leak
      Connection flooding
      Pairing hijack
    Tech stack
      Python
      BlueZ
      l2flood
    Use cases
      Test own devices
      Study pairing gaps
      Research disclosure
    Audience
      Security researchers
    Requirements
      Linux root access
      Written authorization
    Legal
      CFAA warning

Code map

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What do people build with it?

USE CASE 1

Study how Bluetooth address privacy can be bypassed on Fast Pair devices you own.

USE CASE 2

Test whether your own Bluetooth device is vulnerable to connection flooding.

USE CASE 3

Research pairing security gaps that occur during a Bluetooth stack's recovery window.

What is it built with?

PythonBlueZl2flood

How does it compare?

ymsniper/whisper_bully410979729/scope-recallabdullahselek/reducepy
Stars333333
LanguagePythonPythonPython
Last pushed2022-04-03
MaintenanceDormant
Setup difficultyhardmoderatemoderate
Complexity4/53/53/5
Audienceresearcherdeveloperdeveloper

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · hard Time to first run · 1h+

Requires Linux with root access, BlueZ, and a separately built l2flood tool with OpenMP support.

The README does not state a license for this code.

In plain English

Whisper Bully is a Bluetooth security research tool written in Python. It targets devices that advertise Google's Fast Pair feature, and it demonstrates three attack stages the author says are not fixed by an existing patch known as CVE-2025-36911. The first stage extracts a device's permanent hardware address. Normally a Bluetooth device hides this address behind a rotating, temporary one for privacy. The tool connects to the device using a plain Bluetooth connection, then reads a cached value from the Linux Bluetooth stack to recover the real, permanent address, without needing to interact with the Fast Pair protocol at all. The second stage floods the target device with rapid connect and disconnect attempts using a modified version of a tool called l2flood. This can make the device unresponsive to normal Bluetooth connections while the flood runs, though the README states the device fully recovers once the flood stops. The third stage tries to pair with the target while it is recovering from the flood. During that recovery window, the tool argues the device accepts a standard pairing request without the extra security check that the Fast Pair protocol would normally require, resulting in a bond that persists even after the flood ends. The project requires Linux with root access, a working BlueZ Bluetooth stack, Python 3.7 or newer, and the separately maintained l2flood tool for the flooding and hijack stages. The README includes an explicit legal warning stating the tool is for research on devices the user owns or has written authorization to test, and that unauthorized use can be a federal crime under the Computer Fraud and Abuse Act. The full README is longer than what was shown.

Copy-paste prompts

Prompt 1
Explain how Whisper Bully recovers a device's permanent Bluetooth address from a rotating one.
Prompt 2
Walk me through the three attack stages this tool uses against Fast Pair devices.
Prompt 3
Help me set up BlueZ and l2flood so I can run this tool against my own hardware.
Prompt 4
Summarize why this tool's findings differ from the CVE-2025-36911 patch.

Frequently asked questions

What is whisper_bully?

Whisper Bully is a Bluetooth research tool that extracts a device's real address, floods it offline, then hijacks the pairing bond during recovery.

What language is whisper_bully written in?

Mainly Python. The stack also includes Python, BlueZ, l2flood.

What license does whisper_bully use?

The README does not state a license for this code.

How hard is whisper_bully to set up?

Setup difficulty is rated hard, with roughly 1h+ to a first successful run.

Who is whisper_bully for?

Mainly researcher.

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