How to mirror the traffic of wireless IoT on networks

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Mirroring the communication traffic of wireless IoT devices on a network is essential for security monitoring, troubleshooting, and protocol analysis. Below is a detailed step-by-step guide on how to achieve this effectively.

1. Understanding Traffic Mirroring for Wireless IoT Devices

Unlike traditional wired networks where port mirroring (SPAN) on a switch can be used to duplicate traffic, wireless networks require a different approach because IoT devices communicate over Wi-Fi, Zigbee, Bluetooth, LoRa, or other protocols. The goal is to capture and analyze the traffic without disrupting the normal functioning of the IoT devices.

Common Methods for Capturing Wireless IoT Traffic:

  1. Wi-Fi Packet Sniffing (Monitor Mode)

  2. Access Point (AP) Traffic Mirroring

  3. Network TAP (Test Access Point) for Wireless

  4. Software-Based Mirroring (Using Raspberry Pi or a dedicated system)

  5. Router-based Traffic Mirroring (DD-WRT, OpenWRT, pfSense)

  6. IoT Gateway Traffic Mirroring

  7. Zigbee and Bluetooth Sniffing

2. Wi-Fi Packet Sniffing (Monitor Mode)

Monitor Mode allows a network adapter to capture all Wi-Fi traffic on a specific channel, even if it's not directed to the system running the capture.

Steps to Capture Wireless IoT Traffic in Monitor Mode

Hardware Requirements:

  • A Wi-Fi adapter that supports Monitor Mode and Packet Injection (e.g., Alfa AWUS036NHA, TP-Link TL-WN722N v1).

  • A Linux system (Kali Linux, Ubuntu) or a macOS device.

Setup Process:

  1. Identify the Wireless Interface: iwconfig

  2. Enable Monitor Mode on the Adapter: sudo airmon-ng start wlan0

  3. Capture Packets Using Wireshark or Tcpdump: sudo tcpdump -i wlan0mon -w iot_traffic.pcap

    • Alternatively, open Wireshark, select wlan0mon, and start capturing packets.

  4. Filter IoT Traffic: Use display filters in Wireshark

    • wlan.addr == XX:XX:XX:XX:XX:XX (Filter by MAC address)

    • ip.addr == 192.168.1.X (Filter by IP address)

    • mqtt (Filter MQTT traffic)

    • coap (Filter CoAP traffic)

  5. Analyze the Traffic:
    Look for HTTP, MQTT, CoAP, or encrypted TLS traffic from IoT devices.

Pros: 

  • No need to modify the network.
  • Works with any IoT device using Wi-Fi.
  • Captures all broadcast and unicast traffic on the same Wi-Fi channel.

Cons: 

  • Cannot capture traffic on multiple Wi-Fi channels simultaneously.
  • Cannot decrypt WPA2-PSK traffic without a known key.

3. Access Point (AP) Traffic Mirroring

If you own the wireless access point, you can configure port mirroring to forward IoT traffic to an analysis system.

Steps:

  1. Log into your Wi-Fi router or Access Point.

  2. Enable Port Mirroring (or SPAN) if available.

  3. Set a destination system (e.g., your PC) to receive mirrored traffic.

  4. Use Wireshark or tcpdump to capture traffic.

Pros: 

  • Works at the network level without needing special adapters.
  • Captures all device traffic without needing Monitor Mode.

Cons: 

  • Not all consumer routers support mirroring.
  • Cannot capture encrypted traffic without access to keys.

4. Using a Wireless Network TAP

A Wireless Network TAP (Test Access Point) acts as an intermediary device that forwards traffic to an analysis system.

Setup Process:

  1. Deploy a TAP device (e.g., Great Scott Gadgets’ Packet Squirrel).

  2. Configure the TAP to forward IoT traffic to a logging system.

  3. Capture and analyze packets using Wireshark or Suricata.

Pros: 

  • Non-intrusive, no modification to network required.
  • Works with encrypted traffic if placed at the gateway.

Cons: 

  • Expensive compared to software-based solutions.
  • Requires additional hardware.

5. Software-Based Traffic Mirroring (Using Raspberry Pi or Dedicated System)

If you have a Raspberry Pi or a dedicated Linux system, you can mirror IoT traffic to a monitoring system.

Steps:

  1. Setup a Raspberry Pi as an AP: sudo apt install hostapd dnsmasq

  2. Enable Traffic Forwarding & Mirroring:

    sudo iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

  3. Capture the traffic using Wireshark on the monitoring device.

Pros: 

  • Cost-effective, no need for special hardware.
  • Works with encrypted traffic if placed as a proxy.

Cons: 

  • Requires manual setup.
  • Limited by the Raspberry Pi's processing power.

6. Router-based Traffic Mirroring (DD-WRT, OpenWRT, pfSense)

Advanced router firmware like DD-WRT, OpenWRT, or pfSense allows you to mirror traffic to a remote capture system.

Steps:

  1. Install tcpdump on the router.

  2. Configure traffic mirroring: tcpdump -i wlan0 -w /tmp/iot_traffic.pcap

  3. Transfer the file for analysis: scp root@router:/tmp/iot_traffic.pcap .

  4. Open it in Wireshark.

Pros: 

  • Works directly on the router.
  • No need for extra monitoring devices.

Cons: 

  • Requires custom firmware.
  • Can impact router performance.

7. Zigbee and Bluetooth IoT Sniffing

For Zigbee (2.4 GHz) and Bluetooth IoT devices, you need a dedicated sniffer.

Required Hardware:

  • Zigbee Sniffer: TI CC2531 USB Dongle, HackRF, or Ubertooth One.

  • Bluetooth Sniffer: Nordic Semiconductor nRF52840 Dongle.

Capturing Zigbee Traffic:

  1. Install Zigbee2MQTT and configure sniffing mode.

  2. Use Wireshark to analyze captured Zigbee packets.

Capturing Bluetooth Traffic:

  1. Set the Bluetooth adapter in sniffing mode: hcitool scan

  2. Use Wireshark with Bluetooth filters.

Pros: 

  • Works for non-Wi-Fi IoT devices.
  • Effective for Zigbee & Bluetooth security analysis.

Cons: 

  • Requires specialized hardware.
  • Limited to specific frequencies.

Final Recommendations

MethodBest ForComplexityCost
Monitor Mode SniffingWi-Fi IoT DevicesMediumLow
AP Traffic MirroringEnterprise NetworksHighMedium
Network TAPIndustrial NetworksHighHigh
Raspberry Pi ProxyHome IoT NetworksMediumLow
Router MirroringNetwork-wide captureHighMedium
Zigbee/Bluetooth SniffingNon-Wi-Fi IoTHighMedium

Choosing the right method depends on:

  • IoT Device Type (Wi-Fi, Zigbee, Bluetooth)
  • Network Topology (Home, Industrial, Enterprise)
  • Security Needs (Encrypted vs. Plaintext Traffic)




#CPS #OT #XIoT #IoT #IIoT #IoMT #CPSSecurity #OTSecurity #IoTSecurity #CPS보안 #OT보안 #IoT보안

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