Several Broadcom/Cypress Bluetooth firmwares and their firmware update mechanism have been reverse engineered. Based on that we developed a Bluetooth experimentation framework which is able to patch the firmware and therefore implement monitoring and injection tools for the lower layers of the Bluetooth protocol stack.
Publications and Background
Master Thesis (07/2018)
MRMCD Talk (09/2018)
The basic framework for Nexus 5 / BCM4339 was presented at the MRMCD Conference 2018 in Darmstadt. The talk was also recorded and includes an overview of the framework as well as two demo usages at the end (Following a Secure Simple Pairing procedure in Wireshark and implementing a proof of concept for CVE-2018-5383).
35C3 Talk (12/2018)
More extensions were presented at 35C3 2018 in Leipzig. New features include creating connections to non-discoverable devices. Moreover, we gave a demo of CVE-2018-19860, which can crash Bluetooth on several Broadcom chips. This talk was also recorded and gives a more high level overview.
TROOPERS Talk (03/2019)
WiSec Paper (05/2019)
Our WiSec paper Inside Job: Diagnosing Bluetooth Lower Layers Using Off-the-Shelf Devices on reversing the Broadcom Bluetooth diagnostics protocol was accepted, demonstrated and got the replicability label.
MobiSys Paper (06/2019)
Our MobiSys paper InternalBlue - Bluetooth Binary Patching and Experimentation Framework on the complete InternalBlue ecosystem got accepted.
REcon Talk (06/2019)
We gave a talk at REcon, Reversing and Exploiting Broadcom Bluetooth. It provides a first intuition on how to do binary patching in C with Nexmon to change Bluetooth functionality.
MRMCD Talk (09/2019)
Our talk Playing with Bluetooth focuses on new device support within InternalBlue and the Patchram state of various devices.
36C3 Talk (12/2019)
The rather generic talk All wireless communication stacks are equally broken points out a couple of new research directions and new Bluetooth projects coming up.
EWSN Paper & Demo (02/2020)
We did some work on improving blacklisting performance of BLE data connections. Currently in a separate blacklisting branch.
This list is subject to change, but we give you a brief overview. You probably have a platform with a Broadcom chip that supports most features :)
On any Bluetooth chip:
- Send HCI commands
- Monitor HCI
- Establish connections
On any Broadcom Bluetooth chip:
- Read and write RAM
- Read and write assembly to RAM
- Read ROM
- Set defined breakpoints that crash on execution
- Inject arbitrary valid LMP messages (opcode and length must me standard compliant, contents and order are arbitrary)
- Use diagnostic features to monitor LMP and LCP (with new Android H4 driver patch, still needs to be integrated into BlueZ)
- Read AFH channel map
On selected Broadcom Bluetooth chips:
- Write to ROM via Patchram (any chip with defined firmware file >= build date 2012)
- Interpret core dumps (Nexus 5/6P, Samsung Galaxy S6, Evaluation Boards, Samsung Galaxy S10/S10e/S10+)
- Debug firmware with tracepoints (Nexus 5 and Evaluation Board CYW20735)
- Fuzz invalid LMP messages (Nexus 5 and Evaluation Board CYW20735)
- Inject LCP messages, including invalid messages (Nexus 5, Raspberry Pi 3/3+/4)
- Full object and function symbol table (Cypress Evaluation Boards only)
- Demos for Nexus 5 only:
- ECDH CVE-2018-5383 example
- NiNo example
- MAC address filter example
- KNOB attack test for various devices, including Raspberry Pi 3+/4
A comprehensive list of chips and which devices have them can be found in the firmware module documentation.
- Ideally recompiled
bluetooth.default.so, but also works on any rooted smartphone, see Android instructions
- Android device connected via ADB
- Best support is currently given for Nexus 5 / BCM4339 and Evaluation Boards
- Optional: Patch for Android driver to support Broadcom H4 forwarding
- Optional, if H4: Wireshark Broadcom H4 Dissector Plugin
- BlueZ, instructions see here
- Best support for Raspberry Pi 3/3+/4
- For most commands: Privileged access
- A jailbroken iOS device (tested on iOS 12.1.2/12.4 with iPhone 6, SE, 7, 8, X)
- The included
ios-proxy(instructions in here)
- Optional: a Mac with
xcodeto compile the proxy yourself
- Optional, no jailbreak required: install iOS Bluetooth Debug Profile to obtain HCI and diagnostic messages, either via diagnostic report feature (all iOS versions) or live with PacketLogger (since iOS 13)
- Xcode 10.2.1
- Instructions see here
Setup and Installation
The framework uses ADB (Android Debug Bridge) to connect to an Android smartphone, BlueZ sockets on Linux, or the included iOS Proxy on iOS.
For Android with ADB, either connect the phone via USB or setup ADB over TCP and make sure you enable USB debugging in the developer settings of Android.
If you have a jailbroken iOS device, you need to install a proxy that locally connects to the Bluetooth device and forwards HCI commands and events.
On Linux with BlueZ, everything should work out of the box, but you need to execute InternalBlue as root for most features.
The InternalBlue framework is written in Python 2. You can install it together with all dependencies by using pip:
git clone https://github.com/seemoo-lab/internalblue.git cd internalblue pip2 install .
It will install the following dependencies:
The pwntools module needs the binutils package for ARM 32-bit to be installed on the system. This has to be installed manually by using the packet manager of your Linux distribution:
# for Arch Linux sudo pacman -S arm-none-eabi-binutils # for Ubuntu sudo apt install binutils-arm-linux-gnueabi
All steps on a plain Ubuntu 18.04:
sudo apt install git python-setuptools binutils-arm-linux-gnueabi adb pip python-dev gcc git clone https://github.com/seemoo-lab/internalblue cd internalblue sudo pip2 install . cd .. sudo apt-get install wireshark-dev wireshark cmake git clone https://github.com/seemoo-lab/h4bcm_wireshark_dissector cd h4bcm_wireshark_dissector mkdir build cd build cmake .. make make install
Packets required on a current (July 2019) Raspian:
sudo apt-get --allow-releaseinfo-change update sudo apt-get install git python-setuptools binutils-arm-none-eabi adb python-pip python-dev gcc libffi-dev
The CLI (Command Line Interface) of InternalBlue can be started by running:
python2 -m internalblue.cli
The setup.py installation will also place a shortcut to the CLI into the $PATH so that it can be started from a command line using:
It should automatically connect to your Android phone through ADB or your local Linux with BlueZ. With BlueZ, some commands can be sent by unprivileged users (i.e. version requests) and some commands require privileged users (i.e. establishing connections). Use the help command to display a list of available commands. A typical set of actions to check if everything is working properly would be:
wireshark start connect ff:ff:13:37:ab:cd sendlmp 01 -d 02
Note that InternalBlue only displays 4 byte MAC addresses in some places. This is because the leading two bytes are not required by Bluetooth communication, you can replace them with anything you want.
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