Flipper Zero: Choosing the Best Firmware for Pentesting

The Problem: Unlocking the Flipper Zero’s Full Pentesting Potential

The Flipper Zero has taken the tech world by storm, captivating security researchers, hobbyists, and penetration testers with its open-source versatility and community-driven innovation. This pocket-sized powerhouse can interact with access control systems, analyse radio frequencies, and even emulate USB devices, a dream for anyone in cybersecurity. But here’s the catch: while its stock firmware is solid, it’s not enough to fully harness its potential for advanced pentesting. Regional restrictions limit sub-GHz frequency ranges, advanced features like rolling code support are missing, and customisation options are minimal. For security pros and enthusiasts, this creates a dilemma. How do you transform this device into the ultimate pentesting tool tailored to your specific needs?

The firmware you choose defines what the Flipper Zero can do. Picking the wrong one, or sticking with the default means missing out on critical capabilities like extended RF testing, sophisticated Bluetooth attacks, or complex USB exploits. Without understanding its role in your pentest or security engagement, you’re left with a device that’s powerful but underutilized. So, how do you maximize its utility and make it a standout in your cybersecurity toolkit?

The Solutions: Exploring Firmware Options to Supercharge Your Flipper Zero

Fortunately, the Flipper Zero’s open-source nature and vibrant community offer a range of firmware solutions, each designed to address specific pentesting challenges. Here’s how the official firmware stacks up, followed by custom options that push the boundaries.

Official Firmware: A Reliable Starting Point

The official firmware comes pre-installed and offers a stable foundation:

Features:

• Sub-GHz Radio Communication: Operates within legal frequency bands, allowing interaction with various RF devices like garage door openers or keyless entry systems.
• Infrared (IR) Transmit and Receive: Can emulate remote controls for TVs, AC units, and other IR devices.
• NFC Reading and Emulation: Facilitates reading and cloning of NFC tags, which is useful for testing access control systems.
• Bluetooth Low Energy (BLE) Connectivity: For scanning or connecting to nearby BLE devices, useful in security audits.
• GPIO for Hardware Hacking: Provides pins for interfacing with external hardware for custom projects.
• Bad USB Capabilities: Allows the device to act as a keyboard, executing scripts when plugged into a computer.

Limitations:

• Regional Restrictions: The official firmware adheres to local regulations which can limit sub-GHz frequencies.
• Limited Advanced Features: Lacks some advanced functionalities that could be beneficial for thorough security testing.

It’s perfect for beginners or basic tasks, but for serious pentesting, you’ll need more firepower.

Custom Firmware: Tailored Power for Pros

Custom firmware unlocks the Flipper Zero’s true potential, offering advanced features and flexibility.

Advantages:

• Extended Frequency Ranges: Opens up more sub-GHz bands for testing beyond legal limits, useful for comprehensive RF security assessments.
• Support for Rolling Code Protocols: Critical for interacting with security systems using dynamic codes, enhancing the depth of pentesting.
• Advanced Security Measures: Includes tools for more sophisticated security evaluations, like Bluetooth spam or custom attack payloads.
• Interface Customization: Offers users the ability to tailor the user interface to their workflow, enhancing usability.
• Community-developed Plugins: Expands functionality with plugins like frequency analysers, fuzzers for testing device robustness, or specific protocol support.

Popular Custom Firmware Options

Unleashed: RF Mastery Unleashed

Unleashed is a widely popular custom firmware that removes regional restrictions and enhances stability while offering additional security tools. It is ideal for penetration testers who need extended frequency support and advanced RF analysis capabilities.

Key Features:

• Stability Upgrades: Ensures smoother operation with fewer crashes or freezes.
• No Regional Restrictions: Allows testing across a broader spectrum of frequencies.
• Rolling Code Protocol Support: Specifically for testing security of rolling code systems.
• Community Plugins: Includes tools like a new frequency analyser for in-depth RF analysis and LF RFID and iButton Fuzzer for testing vulnerabilities in low-frequency RFID systems .

Benefits:

• Enhanced Battery Life: Optimizations that extend the device's operational time.
• Faster Bluetooth Connection: Particularly with Android devices, improving user experience.
• Faster Firmware Updates: Streamlining the process of keeping the device up-to-date.

Momentum: Customization and Bluetooth Brilliance

Momentum is designed for users looking for extensive UI customisation, advanced Bluetooth security testing, and improved file management. It provides unique tools like BLE spam and GPS sub-driving, making it a solid choice for those focused on diverse attack vectors.

Key Features:

• Find My BadKB: A feature to locate your Flipper Zero if misplaced, using BLE signals .
• BLE Spam: A set of tools for testing Bluetooth security by overwhelming devices with connections or data.
• GPS Sub-driving: Potentially for tracking or simulating GPS signals for testing purposes ³.
• UI Customization: Multiple menu styles and a control centre for quick access to functions ³.
• Advanced File Browser/Manager: Enhances file management on the device, crucial for handling scripts or logs

Benefits:

• Redesigned Interface: More intuitive and tailored to the needs of pentesters .
• Quick Toggles: For immediate access to frequently used features .

RogueMaster: The All-Rounder

RogueMaster merges the best features of Unleashed and Xtreme (a firmware option not covered here as it is no longer supported), making it a versatile option for users of all experience levels. It includes enhancements for Bad USB attacks, custom apps, and a simplified interface mode for streamlined operations.

Key Features:

• Combination of Unleashed and Xtreme: Merges the best features of both, providing versatility.
• DUMB Mode: Simplifies the interface for less experienced users or quick operations.
• Custom Apps and Animations: Enhances user interaction with unique applications and visual feedback .

Benefits:

• Versatility: Suitable for both novice and expert users, balancing functionality with ease of use .
• Bad USB Enhancements: Offers extensive control over keyboard emulation for complex attack patterns.

Key Features for Pentesting

• Extended Sub-GHz Capabilities: Allows for the testing of RF devices from different regions or with non-standard frequencies, crucial for comprehensive security analysis .
• Rolling Code Support: Essential for penetration testing of systems using dynamic code encryption for security, like modern car key fobs .
• Advanced Security Measures: Tools like BLE spam help in assessing Bluetooth vulnerabilities, testing network defences, or simulating attack scenarios .
• Bad USB Enhancements: Customizable scripts and keyboard layouts enable very specific attack vectors, from simple keystroke injections to complex macro execution .
• Customization Options: Tailoring the Flipper Zero's interface and functionality to match specific pentesting tasks or personal workflow preferences .
• HID Attacks: Utilizes the device's ability to mimic USB HID devices for executing commands on target systems, potentially bypassing security measures .

Reviews and Comparisons

‍

Latest Flipper Zero Apps

• Evil Crow RF V2: Not only replays but also analyses and records new sub-GHz signals for testing or cloning
• Find My BadKB: Uses BLE to emit a signal that can be picked up by apps or other Flipper devices to locate the lost unit
• BLE Spam: Tools for both ethical hacking and pranking, simulating multiple device connections to test system resilience
• Video Game Module Tool: Offers customization of game modules, firmware updates, and even colour adjustments for the display
• USB Mass Storage: Can be used to transfer data or serve as a decoy storage for security tests
• Universal Remotes: Includes scripts for various devices, potentially extending beyond home entertainment systems
• UniRF Remix: A tool for those deeply involved in RF security, allowing signal manipulation at a more advanced level
• Games: Not just for downtime, can be used to understand hardware interactions or as part of security challenges
• NFC Apps: From reading MIFARE cards to emulating transit passes, these apps cover a wide range of NFC operations
• Fuzzers: For testing how devices handle unexpected data, crucial for finding security weaknesses in IoT or access systems.
• Temperature Sensor Readers: Useful in scenarios where environmental data might be part of security or automation systems
• Authenticators: Can simulate security keys, useful for testing authentication systems
• GPIO Apps: Allows for intricate control over external hardware, expanding  the Flipper's capabilities for custom security tools

Expanding Flipper Zero with External Devices via GPIO

Beyond firmware, the Flipper Zero’s GPIO pins connect to external hardware like WiFi devboards (for packet sniffing), sub-GHz modules (for wider RF range), or sensors (for IoT testing). Apps like Evil Crow RF V2, NFC emulators, and fuzzers further amplify its capabilities, turning it into a hardware hacking beast.

Key External Devices and Their Advantages

Sub-GHz Modules

• Expands the frequency range of the Flipper Zero, allowing interaction with a wider range of RF signals.
• Useful  or advanced security testing of remote keyless entry systems, IoT devices, and access control mechanisms.

WiFi Devboard

• Enables packet sniffing, deauthentication attacks, and WiFi network security assessments.
• Allows interaction with WiFi-enabled IoT devices for security testing and debugging.

Sensors (Temperature, Environmental, and Motion Sensors)

• Provides real-time environmental monitoring, which can be useful for security applications.
• Can be used in IoT security assessments, ensuring devices respond correctly to external stimuli.

Custom Hardware Development Boards

• Facilitates the creation of unique security testing tools tailored to specific needs.
• Encourages hardware security research by integrating the Flipper Zero with various microcontrollers and circuits.

Video Game Module

• Adds a Raspberry Pi RP2040 microcontroller, motion-tracking sensor, and video output capabilities.
• Expands the scope of Flipper Zero beyond pentesting, enabling development in gaming and UI experimentation.

GPIO Applications in Security Research

• Hardware Hacking: Interfacing with and testing embedded systems.
• Home Automation Security: Testing the resilience of IoT home automation devices.
• Protocol Analysis: Using the GPIO for debugging and exploring various digital communication protocols.

Expanding the Flipper Zero with these external devices significantly broadens its capabilities, making it an essential tool for cybersecurity professionals, hardware hackers, and researchers. As new external modules are developed, the Flipper Zero community continues to push the boundaries of what this device can achieve.

Choosing and Installing Your Firmware

Choosing the Right Firmware

• Experience Level: Start with official firmware to understand basic operations before advancing to custom solutions.
• Pentesting Focus: If your work involves a lot of RF analysis, consider Unleashed; for broader security testing with customization, Momentum; for versatile USB attacks, RogueMaster.
• Community Support: Ensure the firmware has active community support for updates, bug fixes, and user assistance.

Installing Custom Firmware

Backup: Always backup data using qFlipper to prevent loss of configurations or data .

Installation Steps:

• Download: From reputable sources like GitHub, ensuring you get the latest stable version.
• SD Card Preparation: New or freshly formatted to avoid conflicts.
• File Transfer: Firmware files should be at the root of the SD card.
• Flashing: Use the device's menu to initiate the firmware update, following on-screen prompts.
• Post-Installation: Verify all functions work as expected, possibly needing to reconfigure some settings .

Conclusion

The Flipper Zero is more than a gadget, it’s a pentesting Swiss Army knife, and the firmware you choose is the blade that sharpens its edge. Whether you stick with the official firmware’s reliability or dive into custom options like Unleashed, Momentum, or RogueMaster, understanding your security goals is the key to unlocking its full potential. Each solution offers unique strengths, from RF mastery to Bluetooth trickery to USB wizardry, ensuring there’s a fit for every pentester’s playbook.  

Stay engaged with the Flipper community. Its dynamic evolution means new features, plugins, and hardware integrations are always on the horizon. Pick the right firmware, pair it with GPIO add-ons or killer apps, and transform your Flipper Zero into a cybersecurity titan. Ready to take your security research to the next level? The power’s in your hands. Choose wisely and start exploring!  

‍

‍