26zl LoRaWAN & Sub-GHz Attacks
LoRaWAN provides long-range low-bitrate communication for IoT — common in smart cities, asset tracking, and industrial telemetry. Outside LoRaWAN, the 433 / 868 / 915 MHz ISM bands host garage doors, doorbells, smart plugs, weather stations, and TPMS — most with weak or no crypto.
Quick Workflow
- Identify the band + modulation (LoRa CSS vs. simple OOK/FSK)
- Capture transmissions with appropriate hardware (HackRF / RTL-SDR / Flipper Zero)
- For LoRaWAN: capture join + uplinks; analyze key derivation
- For proprietary sub-GHz: demodulate, identify packet format, replay or craft
Hardware
| Tool | Range | Use |
|---|---|---|
| RTL-SDR | RX only, 24 MHz–1.7 GHz | Cheap reconnaissance |
| HackRF One | RX/TX, 1 MHz–6 GHz | Full transceiver |
| Flipper Zero | RX/TX, sub-GHz | Quick replays, fixed-code attacks |
| LimeSDR / BladeRF | RX/TX, wider band | Higher fidelity for LoRaWAN |
| YARD Stick One | TX-focused sub-GHz | Targeted replays |
| LoRa-specific gateway (RAK / Heltec) | LoRaWAN dual-direction | Standards-compliant LoRaWAN testing |
LoRaWAN
LoRaWAN is a MAC layer over LoRa physical (chirp spread spectrum). Devices either:
- OTAA (Over-the-Air Activation) — derive session keys at join
- ABP (Activation By Personalization) — pre-flashed keys
OTAA Join Capture
# Capture LoRa packets with HackRF + Inspectrum
hackrf_transfer -r capture.iq -f 868000000 -s 1000000 -n 60000000
# Or LoRa-specific: rak_common_for_gateway
# Decode with PHY + MAC stack
git clone https://github.com/Lora-net/LoRaMac-node
# Or use ChirpStack as a sniffing gateway
The Join-Request and Join-Accept are encrypted with the device's AppKey. With AppKey (extracted from device firmware — see offensive-iot):
- Decrypt Join-Accept → recover NwkSKey, AppSKey
- Subsequent traffic decryption + injection
ABP — Pre-Flashed Keys
ABP devices have NwkSKey + AppSKey flashed at manufacture. Common flaws:
- Same key across thousands of devices (vendor laziness)
- No frame counter rollover protection → replay any historical uplink
- DevAddr predictability (sequential allocation)
# If you have NwkSKey + AppSKey + DevAddr, decode/inject with lorawan-test-tools
git clone https://github.com/IoTsec/loraserver-attack-tools
python lora_inject.py --nwkskey <NWKS> --appskey <APPS> --devaddr <ADDR>
Frame Counter Replay
Older LoRaWAN 1.0.x doesn't enforce strict frame counter monotonicity in all stacks. Replay an uplink with a different timestamp → server processes as fresh.
Downlink Injection
If you control AppSKey + NwkSKey, you can inject downlinks (configuration changes, remote commands) to devices.
Sub-GHz Proprietary Protocols
Quick Capture + Replay (Flipper Zero / HackRF)
# RTL-SDR live monitor
rtl_433 -f 433.92M -A # auto-decode many devices
gqrx # interactive spectrum analyzer
# Flipper Zero Sub-GHz menu: Read → identify modulation → capture → save
# Then replay from the saved file
# HackRF capture
hackrf_transfer -r garage.iq -f 433920000 -s 8000000 -n 80000000
# Inspectrum to visualize, identify OOK / FSK, decode bits
KeeLoq (Old Garage Doors, Some Cars)
KeeLoq uses a 32-bit block cipher with a manufacturer key. The manufacturer key was extracted publicly years ago for major brands. With it:
- Decrypt rolling code → predict next valid code
- Combined with capture-replay, take over the remote
# rolling-code-tools (research)
git clone https://github.com/AndrewMohawk/RollingPwn
Modern KeeLoq deployments (last 5 years) have rotated manufacturer keys, but legacy hardware (older garage doors, some industrial equipment) is in scope.
Fixed-Code Remotes
Many cheap garage openers, doorbells, and smart plugs use fixed codes — the same packet every time you press the button. Capture once, replay forever.
# Flipper Zero: Read → Save → Send (from saved file)
# Or with RFCat:
python -c "import rflib; ..."
# OR with HackRF:
hackrf_transfer -t replay.iq -f 433920000 -s 8000000
TPMS Spoofing
Tire-pressure monitoring sensors broadcast at 315/433 MHz with no authentication. Spoof low-pressure alerts:
# Capture legitimate TPMS
rtl_433 -f 315M -F json | grep TPMS
# Synthesize crafted alerts (custom modulator with HackRF)
# Useful for testing TPMS-aware vehicle systems or as denial-of-trust attack
Reconstruction of Unknown Protocols
# Universal Radio Hacker (URH) — visual reverse engineering
urh
# Load .iq capture, identify modulation visually,
# auto-detect symbols, decode bits, identify packet structure
URH walks you from raw RF to a parsed protocol description, even with no docs.
Engagement Cheatsheet
# 1. Identify band + modulation
rtl_433 -f <freq> -A # auto-detect known protocols
gqrx # spectrum view to find activity
# 2. For LoRaWAN
# - Set up gateway (or HackRF + LoRa decoding)
# - Capture joins + uplinks
# - Extract keys from device firmware (see offensive-iot)
# 3. For proprietary sub-GHz
# - Capture with HackRF / RTL-SDR
# - Visualize / decode with Inspectrum or URH
# - Replay or craft
# 4. Document modulation, frequency, packet format, replay viability
Detection
- LoRaWAN networks have server-side anomaly detection (frame counter, signal strength, geographic) — varies widely by operator
- Sub-GHz consumer products typically have no monitoring
- TPMS / industrial equipment has minimal telemetry on RF anomalies
Reporting
- Identify exact frequency, modulation, baud, and packet format per device
- Distinguish capture-replay vs. crafted-frame attacks
- Note crypto state (cleartext / weak-fixed-key / standards-compliant)
- For LoRaWAN: identify AppKey / NwkSKey / AppSKey storage in firmware
Key References
- rtl_433 protocol database: github.com/merbanan/rtl_433
- Universal Radio Hacker: github.com/jopohl/urh
- RollingPwn (KeeLoq research): github.com/AndrewMohawk/RollingPwn
- LoRaWAN Specification: lora-alliance.org
- Source: https://github.com/SnailSploit/offensive-checklist/blob/main/wireless.md