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Introduction:
The Flipper Zero has become the pentester’s Swiss Army knife for attacking RFID, NFC, infrared, and sub-GHz wireless systems. Now, a 3D-printed “Flipper One” model – shared by ESET malware researcher Lukas Stefanko – signals a new wave of DIY, customizable clones that lower the barrier for both ethical hackers and adversaries. This article compares the original Flipper Zero with the emerging 3D-printed Flipper One, then delivers hands-on training on how to detect, exploit, and harden against such RF hacking tools using Linux/Windows commands, cloud hardening, and API security controls.
Learning Objectives:
- Analyze hardware differences between Flipper Zero and a 3D-printed clone (Flipper One) for offensive security use cases.
- Execute RF replay attacks, brute-force rolling codes, and capture sub-GHz signals using open-source tools on Linux/Windows.
- Implement mitigations: rolling code patches, signal filtering, cloud WAF rules, and firmware integrity checks.
You Should Know:
- Reverse‑Engineering the Flipper One – From STL Files to Functional Attack Tool
The Flipper One is a community-driven, 3D-printable shell (STL files available on GitHub) designed to host an ESP32-S3 or RP2040 with CC1101, PN532, and other radio modules. Unlike the polished Flipper Zero, the One requires soldering, manual firmware flashing, and driver configuration. However, its open-source nature allows attackers to embed hidden triggers (e.g., delayed payloads) or combine Wi-Fi deauthentication with RFID cloning.
Step‑by‑step guide: Building a test clone (for authorized labs only)
On Linux (Ubuntu 22.04):
Clone the Flipper One firmware (example – actual repo varies) git clone https://github.com/example/flipper-one-fw cd flipper-one-fw Install dependencies for ESP32 sudo apt install gcc-xtensa-esp32 python3-pip pip install esptool Build and flash to ESP32-S3 idf.py set-target esp32s3 idf.py build idf.py -p /dev/ttyUSB0 flash monitor
On Windows (using WSL or native):
Install WSL2 and Ubuntu, then follow Linux steps above Or use ESP-IDF Command Prompt (cmd) esptool.py --chip esp32s3 --port COM3 write_flash 0x0 firmware.bin
What this does – The build process compiles a radio stack that can capture 433 MHz garage door openers, emulate Mifare Classic cards, and brute‑force fixed‑code key fobs. Use it to test your own physical access controls.
Training course tie‑in: SANS SEC617 – Wireless Ethical Hacking covers similar RF reverse‑engineering with HackRF and YARD Stick One.
- Live Attack Simulation – Replay a Fixed‑Code Signal Captured by Flipper Zero/One
Many legacy access systems use unencrypted, fixed‑code rolling (e.g., KeeLoq without proper implementation). A Flipper or clone can record and replay these signals. Below, we replicate the attack using an RTL-SDR (cheaper alternative) on Linux.
Step‑by‑step guide: Capture and replay 433.92 MHz
Install rtl-sdr and GNU Radio dependencies sudo apt install rtl-sdr gr-osmosdr gqrx-sdr Record raw IQ samples (frequency 433.92M, sample rate 2.4M) rtl_sdr -f 433920000 -s 2400000 -g 40 -1 10000000 capture.bin Convert to WAV for analysis in Audacity (optional) sox -t raw -r 2400000 -e signed -b 16 -c 2 capture.bin capture.wav Replay using HackRF or Flipper Zero’s GPIO-connected CC1101 For Flipper: copy .sub file to SD card (use Flipper CLI) flipper-cli -p /dev/ttyACM0 subghz tx -f 433920000 -d capture.sub
Windows alternative (using SDR and Flipper Zero QFlipper):
- Download SDR (SDRSharp), tune to 433.92 MHz, record baseband.
- Convert to .sub using `subghz_tool.exe` from Flipper Zero firmware tools.
3. Upload via QFlipper desktop app and replay.
Mitigation: Implement rolling codes with secure algorithm (e.g., AES‑128 or SHA‑256 based) and enable replay detection on your access controller. For cloud APIs protecting IoT devices, add rate‑limiting and anomaly detection (e.g., multiple repeated codes from same device fingerprint).
- Hardening APIs Against Cloned Device Attacks – From RF to REST
Modern attacks chain RF cloning with API abuse. For example, a cloned Flipper might emulate a smart lock that calls a cloud API with a stolen device ID. Below we harden the backend with AWS WAF and API Gateway.
Step‑by‑step cloud hardening:
AWS CLI: Create a WAF rule to block repeated invalid rolling codes aws wafv2 create-rule-group --1ame RollingCodeAnomaly --scope REGIONAL --capacity 500 --visibility-config SampledRequestsEnabled=true,CloudWatchMetricsEnabled=true,MetricName=RollingCodeAnomaly Add rate-based rule: >5 failed code attempts per 5 minutes triggers block aws wafv2 create-rate-based-statement --limit 5 --aggregate-key IP --forwarded-ip-config "ForwardedIpHeader=X-Forwarded-For, FallbackBehavior=MATCH" Attach to API Gateway aws apigateway update-stage --rest-api-id <api-id> --stage-1ame prod --patch-operations op=replace,path=/accessLogSettings/destinationArn,value=arn:aws:logs:...
Linux/Windows for API testing – Use `curl` to simulate a cloned device sending old codes:
Linux / WSL – replay captured JWT or device token
for i in {1..10}; do curl -X POST https://api.smartlock.com/unlock -H "Authorization: Bearer $stolen_token" -d '{"code":"1234"}'; done
Defense: Use time‑windowed nonces (TOTP) and mutual TLS (mTLS) for device‑to‑cloud authentication. Disable legacy fixed‑code fallback.
- Detecting Flipper Zero/One Activity on Your Network (Wi‑Fi & Bluetooth)
Flipper devices (with Wi‑Fi dev board or ESP32) can send deauthentication frames, run wardriving, or exfiltrate captured RFID data over BLE. Use `airodump-1g` and `hcitool` to spot them.
Step‑by‑step detection:
Linux – Enable monitor mode and scan for deauth attacks sudo airmon-1g start wlan0 sudo airodump-1g wlan0mon --band abg Look for high deauth packet counts (source MAC often OUI of Espressif) sudo tcpdump -i wlan0mon -e -1 type mgt subtype deauth BLE scanning for Flipper's advertised name sudo hcitool lescan or better: sudo bluetoothctl scan on Flipper Zero advertises as "Flipper Zero XT" or similar.
Windows detection (using Wireshark + Bluetooth LE Explorer):
- Install Wireshark and NPcap, capture on Wi-Fi adapter in monitor mode (if supported).
2. Filter for `wlan.fc.type_subtype == 0x0c` (deauth frames).
- Use Microsoft Bluetooth LE Explorer – scan for devices named “Flipper” or with manufacturer data containing `0xFFFF` (ESPRESSIF).
Response: Immediately ban rogue MACs via `ebtables` (Linux) or `netsh wlan add filter` (Windows). Train blue teams with INE’s eCXD (Certified eXtreme Defense) course.
- Hardening Your Own DIY Clone’s Firmware Against Reverse Engineering
If you build a Flipper One for research, protect your custom capture logic from being dumped by adversaries. Use encrypted flash and secure boot on ESP32.
Step‑by‑step: Enable Flash Encryption on ESP32 (Linux/macOS)
In ESP-IDF environment idf.py menuconfig Navigate to Security features > Enable flash encryption on boot > YES Set Encryption mode: Development (for testing) or Release (production) idf.py build idf.py -p /dev/ttyUSB0 flash monitor On first boot, the chip burns eFuse keys – irreversible!
Post‑encryption verification:
Attempt to read flash via esptool – it will return garbage. To update firmware, sign binaries:
python $IDF_PATH/components/esptool_py/esptool/espsecure.py sign_data --keyfile private_key.bin firmware.bin
Windows alternative – Use ESP-IDF PowerShell environment with same commands.
Security note: This prevents an attacker from extracting your custom attack payloads from a lost Flipper One. Combine with a PIN on the device’s LCD menu.
What Undercode Say:
- Key Takeaway 1 – The 3D‑printed Flipper One lowers the cost of entry from ~$169 (Flipper Zero) to ~$30 in parts, enabling widespread amateur RF hacking. Defenders must shift from “physical security is enough” to continuous wireless monitoring.
- Key Takeaway 2 – Most enterprise IoT and access control systems still rely on fixed‑code or poorly implemented rolling codes. A $30 clone running open‑source firmware can bypass them in seconds. The only real mitigation is cryptographic authentication with short‑lived tokens, plus network anomaly detection.
Analysis: Lukas Stefanko’s comparison highlights an inevitable trend: hardware hacking is becoming fully democratized. While Flipper Zero introduced user‑friendliness, the DIY clone movement (Flipper One, M5Stack variants) means attackers will customize form factors to avoid detection (e.g., hiding inside a USB charger). Red teams should build these clones to test physical perimeters, while blue teams must adopt RF fingerprinting (e.g., signal timing analysis) and deploy software‑defined radio (SDR) sensors at entry points. Training courses from TCM Security (Practical IoT Hacking) and HTB Academy (Hardware Hacking) now include Flipper‑specific modules. Ignore this at your peril – the next breach may come through a 3D‑printed key fob.
Prediction:
- N: By 2026, ready‑to‑print Flipper One kits with stealth enclosures (e.g., inside a pen or badge) will be sold on darknet markets, drastically increasing physical breach attempts against data centers.
- P: Open‑source defensive tools (e.g., RTL‑433 with AI anomaly detection) will mature, allowing small businesses to deploy $50 radio intrusion detection systems, leveling the playing field.
- N: Regulatory bodies like FCC and EU will rush to ban “universal RF cloning devices” – but 3D‑printable designs will remain unregulable, forcing a permanent cat‑and‑mouse game.
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Reported By: Lukasstefanko Comparing – Hackers Feeds
Extra Hub: Undercode MoN
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