Listen to this Post
Introduction
LoRa (Long Range) technology is widely used in IoT and embedded systems for low-power, long-distance communication. However, analyzing LoRa traffic requires specialized tools beyond traditional packet analyzers like Wireshark. In this article, we explore how to build a custom LoRa packet analyzer with protocol dissectors for deep inspection.
Learning Objectives
- Understand the need for custom LoRa traffic analysis tools.
- Learn how to develop a Wireshark-like dissector for LoRa protocols.
- Explore techniques for integrating Software-Defined Radio (SDR) with custom packet inspection.
1. Why Wireshark Isn’t Enough for LoRa Analysis
LoRa operates on proprietary protocols (e.g., Semtech’s SPP), making standard tools like Wireshark insufficient. Below is a Python snippet to capture LoRa packets using a Software-Defined Radio (SDR):
from rtlsdr import RtlSdr import numpy as np sdr = RtlSdr() sdr.sample_rate = 2.048e6 LoRa typical sample rate sdr.center_freq = 868e6 EU LoRa frequency samples = sdr.read_samples(1024 1024)
How to Use:
1. Install `rtlsdr` via `pip install pyrtlsdr`.
- Adjust `center_freq` to match your LoRa band (e.g., 915 MHz for the US).
3. Process raw samples to extract LoRa packets.
2. Building a Custom LoRa Packet Dissector
Wireshark dissectors are written in Lua or C. Below is a basic Lua dissector for LoRa:
local lora_proto = Proto("LoRa", "LoRa Protocol")
function lora_proto.dissector(buffer, pinfo, tree)
pinfo.cols.protocol = "LoRa"
local subtree = tree:add(lora_proto, buffer(), "LoRa Packet")
subtree:add(buffer(0,1), "Preamble: " .. buffer(0,1):uint())
end
register_postdissector(lora_proto)
How to Use:
1. Save as `lora_dissector.lua`.
- Load in Wireshark via
Analyze → Reload Lua Plugins. - Extend with fields like
DevAddr,FCtrl, and payload.
3. Integrating SDR with Custom Packet Analysis
GNU Radio can process LoRa signals before feeding them into a dissector. Example flowgraph:
grcc -d . lora_receiver.grc
Steps:
- Install GNU Radio Companion (
sudo apt install gnuradio).
2. Design a flowgraph to demodulate LoRa signals.
- Pipe output to a custom dissector via UDP.
4. Extracting LoRaWAN Frames
LoRaWAN uses AES-128 encryption. Below is a Python snippet to decrypt payloads:
from Crypto.Cipher import AES
key = bytes.fromhex("2B7E151628AED2A6ABF7158809CF4F3C")
cipher = AES.new(key, AES.MODE_ECB)
decrypted = cipher.decrypt(encrypted_payload)
How to Use:
1. Replace `key` with your LoRaWAN AppSKey/NwkSKey.
2. Decrypt uplink/downlink payloads for analysis.
5. Analyzing LoRa Security Vulnerabilities
LoRa devices are prone to replay attacks. Use `scapy` to craft test packets:
from scapy.all import<br /> pkt = RadioTap() / Dot11() / LoRa() sendp(pkt, iface="wlan0")
Mitigation:
- Enable frame counters in LoRaWAN.
- Use mutual authentication (OTAA).
What Undercode Say
- Key Takeaway 1: Custom dissectors are essential for proprietary protocols like LoRa.
- Key Takeaway 2: SDR integration unlocks real-time LoRa traffic inspection.
Analysis:
The lack of native LoRa support in Wireshark highlights the need for specialized tools. By combining SDR, custom dissectors, and encryption handling, security researchers can gain deep visibility into LoRa networks. Future attacks may target weak key management, making protocol analysis critical.
Prediction
As LoRa adoption grows, expect more attacks on poorly configured devices. Automated tools for LoRa traffic analysis will become a standard in IoT penetration testing.
This guide provides a foundation for building a LoRa-focused packet analyzer. For further reading, explore:
– LoRaWAN Official Docs
– Wireshark Dissector API
– GNU Radio SDR Tutorials
Would you like a deeper dive into any section? Comment below! 🚀
IT/Security Reporter URL:
Reported By: Jahazielleon I – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
