ToothPicker is an in-process, coverage-guided fuzzer for iOS. It was developed to specifically targets iOS's Bluetooth daemon
bluetoothdand to analyze various Bluetooth protocols on iOS. As it is built using FRIDA, it can be adapted to target any platform that runs FRIDA.
This repository also includes an over-the-air fuzzer with an exemplary implementation to fuzz Apple's MagicPairing protocol using InternalBlue. Additionally, it contains the
ReplayCrashFile.pyscript that can be used to verify crashes the in-process fuzzer has found.
This is a very simple fuzzer that only flips bits and bytes in active connections. No coverage-guidance, no injection, but nice as a demo and stateful. Runs just with Python+Frida, no modules or installation required. Tested on iOS 13.5-14.3. See inplace-fuzzer.
The In-Process Fuzzer works out-of-the-box on various iOS versions (13.3-13.7 tested), but symbols need to be specified. Other iOS versions require adaptions to function addresses. Additionally, it seems like FRIDA's stalker has some problems with the iPhone 8. On newer iPhones that support PAC, the performance significantly suffers from signing pointers. Thus, it is recommended to run this on an iPhone 7.
ToothPickeris built on the codebase of frizzer. However, it has been adapted for this specific application as therefore not compatible with the original version anymore. There exist plans to replace this with a more dedicated component in the future.
On the iPhone: - https://frida.re/docs/ios/
For Arch-based Linux: ```bash
sudo pacman -S usbmuxd libimobiledevice python-virtualenv radamsa
sudo systemctl restart usbmuxd
iproxy 4444 44
ssh [email protected] -p 4444
For Debian Linux:
Almost the same as above. Exceptions:
radamsaneeds to be installed from the git repository because it is not packaged.
iproxyrequires the additional package
Slightly different commands compared to the Arch Linux setup...
bash brew install libimobiledevice usbmuxd radamsa npm idevicepair pair npm install frida-compile pip3 install frida-tools
On macOS, PacketLogger, which is part of the Additional Tools for Xcode, can decode various packets once the Bluetooth Debug Profile is installed. Moreover, if you open iOS crash logs with Xcode, it will add some symbols.
Setup: - It is recommended to set up a virtual Python environment for
frizzer. - Install the required packages by running in the
frizzerdirectory. - The
projectsdirectory contains an example project to fuzz the
MagicPairingprotocol. - To build the harness compile the general harness and the specialized
MagicPairingharness into one file. -
harnessdirectory and install
frida-compile. Note that this needs to be run in that folder and can be directly installed as user by running
npm install frida-compile. - Now run
frida-compile ../projects/YOUR_PROJECT/YOUR_SPECIALIZED_HARNESS.JS -o ../projects/YOUR_PROJECT/harness.js. As this was installed in npm context it might require running
npx frida-compileinstead. Each time the harness changes, you need to rerun
Fuzzing: - Connect an iOS device to your computer. - It is advisable to put the phone in flight mode and turn on the "Do not disturb" feature to limit any other activity on the phone. - Run
killall -9 bluetoothdto freshly start
bluetoothd. - Make sure the phone does not connect to other Bluetooth devices. - Now,
cdback into your project's directory, create the crashlog-directory (
mkdir crashes) and run
../../frizzer/fuzzer.py fuzz -p .- Yay! Now collect zero days and obtain large amounts of cash from Apple! (Or collect a huge list of useless NULL-pointer dereferences...)
In short, for starting a new project, run:
bash cd harness npx frida-compile ../projects/YOUR_PROJECT/YOUR_SPECIALIZED_HARNESS.JS -o ../projects/YOUR_PROJECT/harness.js cd ../projects/YOUR_PROJECT/ mkdir crashes ../../frizzer/fuzzer.py fuzz -p .
You can start with a different seed by using
frizzer/fuzzer.py fuzz --seed 1234 -p ..
Adding new iOS versions:
Currently, different versions of iOS are defined in
bluetoothd.js. You can find these with the Ghidra versioning tool given an initial version that has all the required symbols. Note that some of them are not named in the original iOS binary, so ideally start with one that was already annotated before. Each time the
bluetoothd.jschanges, you need to re-run
Increasing bluetoothd capacities:
iOS crash logs are stored in
Settings -> Privacy -> Analytics & Improvements -> Analytics Data. If they contain
bluetoothdcrashes of the pattern
bluetoothd.cpu_resource-*.ipsthis indicates that the crash was caused due to exceeding resources. They can be increased as follows.
On an iPhone 7, run:
bash cd /System/Library/LaunchDaemons/ plistutil -i com.apple.jetsamproperties.D10.plist -o com.apple.jetsamproperties.D10.plist.txt plistutil -i com.apple.jetsamproperties.D101.plist -o com.apple.jetsamproperties.D101.plist.txt
On iPhone SE2, these are in
bash cd /System/Library/LaunchDaemons/ plistutil -i com.apple.jetsamproperties.D79.plist -o com.apple.jetsamproperties.D79.plist.txt
bluetoothd, update the priority to 19 (highest valid priority) and set the memory limit to something very high. Apply the same changes to both files.
ActiveSoftMemoryLimit 24000 InactiveHardMemoryLimit 24000 EnablePressuredExit JetsamPriority 19
Write the changes back and restart
bash plistutil -i com.apple.jetsamproperties.D10.plist.txt -o com.apple.jetsamproperties.D10.plist plistutil -i com.apple.jetsamproperties.D101.plist.txt -o com.apple.jetsamproperties.D101.plist killall -9 bluetoothd
Respectively on the iPhone SE2:
bash plistutil -i com.apple.jetsamproperties.D79.plist.txt -o com.apple.jetsamproperties.D79.plist killall -9 bluetoothd
Deleting old logs:
iOS stops saving crash logs for one program after the limit of 25 is reached. If loading a crash log with Xcode (via Simulators&Devices), some symbols are added to the stack trace. Once the limit is reached, the logs can either be removed via Xcode or directly on the iOS device by deleting them in the folder
Starting from the iPhone XR/Xs, PAC has been introduced. This requires calling
NativeFunctionin FRIDA. While this is a no-op on earlier CPUs, this tremendously reduces speed on newer devices, but is required to make them work at all. We observed that ToothPicker operates at half the speed when using an iPhone SE2 instead of an iPhone 7.
MagicPairingimplementation of the over-the-air fuzzer requires InternalBlue to be installed and can be executed by running
python MagicPairingFuzzer.py TARGET_BD_ADDR.
If you want to reproduce crashes, use the ReplayCrashFile.py script, which can take a crash file and initiates an over-the-air connection with a payload based on the crash.