Your Smart Vacuum is Spying on You: How One Engineer Fought Back Against Forced Obsolescence

Introduction:

The era of Internet of Things (IoT) devices has ushered in unprecedented convenience, but at a hidden cost: user autonomy. A recent incident, where a manufacturer remotely disabled a smart vacuum after its owner opted out of data collection, exposes a critical battle for control in our connected homes. This event is not an anomaly but a stark case study in digital ownership, reverse engineering, and the urgent need for robust consumer cybersecurity.

Learning Objectives:

• Understand the technical methods used to regain control of a locked-down IoT device.
• Learn essential Linux and Python skills for hardware analysis and interaction.
• Implement security hardening techniques to protect your own IoT ecosystem from unauthorized remote access.

You Should Know:

1. Interfacing with IoT Hardware via UART Debugging

Before any code can be run, you must establish a communication channel with the device. Many IoT devices, including smart vacuums, have hidden Universal Asynchronous Receiver-Transmitter (UART) pins on their mainboard for debugging. These pins often provide unauthenticated root shell access.

Verified Linux Command List:

 1. Identify available TTY USB devices
ls /dev/ttyUSB

<ol>
<li>Use a tool like `screen` or `minicom` to connect to the device
sudo screen /dev/ttyUSB0 115200</p></li>
<li><p>If the baud rate is unknown, use a loop to test common rates
for rate in 9600 115200 57600 38400 19200; do
echo "Trying $rate";
sudo screen /dev/ttyUSB0 $rate;
sleep 2;
done</p></li>
<li><p>Use `dmesg` to identify hardware changes when plugging in the device
dmesg | grep tty</p></li>
<li><p>Check for existing serial connections
ls -la /dev/serial/by-id/

Step-by-step guide:

1. Power Down & Disassemble: Safely unplug and open the device’s casing to expose the main printed circuit board (PCB).
2. Locate Pins: Look for a 3 or 4-pin header labeled “UART,” “TX,” “RX,” and “GND.” Sometimes they are unlabeled, requiring a multimeter to identify.
3. Connect Hardware: Using a USB-to-UART adapter (like an FTDI board), connect the adapter’s GND to the device’s GND, TX to RX, and RX to TX.
4. Establish Session: Plug the adapter into your Linux computer. Use the `ls /dev/ttyUSB` command to identify the adapter. Then, use `screen` with a common baud rate (115200 is a frequent default) to connect. If successful, you will see a boot log or a login prompt.

2. Sniffing Network Traffic to Identify Call-Home Domains

Understanding what a device communicates with is crucial. By monitoring its network traffic, you can identify the servers it “phones home” to, which is the first step in blocking them.

Verified Linux Command List:

 1. Start a tcpdump session on the correct interface (e.g., eth0, wlan0)
sudo tcpdump -i eth0 -w vacuum_capture.pcap

<ol>
<li>Monitor traffic in real-time, resolving hostnames
sudo tcpdump -i eth0 -n -A host 192.168.1.100</p></li>
<li><p>Use tshark (Wireshark's CLI) to filter for DNS queries
tshark -i eth0 -Y "dns.qry.name" -T fields -e dns.qry.name</p></li>
<li><p>Perform a continuous ping to monitor latency and packet loss to the device
ping -c 100 192.168.1.100 | grep -oP 'time=\K[^ ]+' | sort -n</p></li>
<li><p>Use nmap to discover open ports on the IoT device
nmap -sS -A -O 192.168.1.100

Step-by-step guide:

1. Set Up Monitoring: Connect the IoT device to a network segment where your Linux machine can see its traffic (e.g., a mirrored port on a switch or the same Wi-Fi network).
2. Start Capture: Run sudo tcpdump -i

    -w capture.pcap</code>. Perform various actions with the vacuum (start cleaning, check status via the app).</li>
   <li><p>Analyze Results: Open the `capture.pcap` file in Wireshark. Filter for DNS queries (<code>dns</code>) and HTTP/HTTPS traffic (<code>http.request.uri</code> or <code>tls.handshake.ja3</code>). The domain names revealed are your targets for blocking.</p></li>
   <li><p>Blocking Unwanted Telemetry with Hosts File and Firewall Rules
   Once you've identified the call-home domains, you can block them at the network level, preventing the device from communicating with the manufacturer's servers.</p></li>
   </ol>
   
   <h2 style="color: yellow;">Verified Linux/Windows Command List:</h2>
   
   <p>[bash]
    LINUX: Edit the hosts file to redirect domains to localhost
   sudo nano /etc/hosts
    Add lines like: 127.0.0.1 api.vacuum-mfg.com data-collector.mfg.org
   
   LINUX: Flush the DNS cache to apply changes
   sudo systemd-resolve --flush-caches
   
   LINUX: Block IP ranges using iptables
   sudo iptables -A OUTPUT -d 203.0.113.0/24 -j DROP
   
   WINDOWS: Edit the hosts file (Run Notepad as Administrator)
   notepad C:\Windows\System32\drivers\etc\hosts
   
   WINDOWS: Flush the DNS cache
   ipconfig /flushdns
   
   WINDOWS: Block an IP using Windows Defender Firewall
   New-NetFirewallRule -DisplayName "Block Vacuum API" -Direction Outbound -Protocol TCP -RemoteAddress 203.0.113.50 -Action Block
   

   Step-by-step guide:

   1. Identify Targets: From your traffic analysis, list all domains and IPs used for telemetry and remote control.
   2. Modify Hosts File: Add each domain to your system's hosts file, pointing it to 127.0.0.1. This makes the device fail to resolve the real server's address.
   3. Implement Firewall Rules: For IP-based blocking or as a secondary measure, create firewall rules that explicitly drop all outbound traffic to the identified IP addresses. This is more robust than DNS blocking alone.

   4. Writing a Custom Python Script for Local Control
      With remote commands blocked, you can write scripts to interact directly with the device's local API, often discovered through network traffic analysis or firmware inspection.

   Verified Python Code Snippet:

   !/usr/bin/env python3
   import requests
   import json
   
   Base URL of the vacuum's local API (discovered via reverse engineering)
   VACUUM_IP = "192.168.1.100"
   BASE_URL = f"http://{VACUUM_IP}/api/v1"
   
   Example: Command to start cleaning
   def start_cleaning():
   endpoint = f"{BASE_URL}/cleaning/start"
    The payload structure is often found in app decompilation or packet capture
   payload = {
   "command": "start",
   "mode": "deep_clean",
   "auth": "local_token"  May require reverse engineering the auth method
   }
   try:
   response = requests.post(endpoint, json=payload, timeout=10)
   if response.status_code == 200:
   print("Cleaning started successfully.")
   else:
   print(f"Failed. Status Code: {response.status_code}")
   except requests.exceptions.RequestException as e:
   print(f"Error: {e}")
   
   Example: Command to get battery status
   def get_battery_status():
   endpoint = f"{BASE_URL}/system/battery"
   response = requests.get(endpoint)
   if response.status_code == 200:
   battery_data = response.json()
   print(f"Battery Level: {battery_data['level']}%")
   else:
   print("Could not retrieve battery status.")
   
   if <strong>name</strong> == "<strong>main</strong>":
   start_cleaning()
   get_battery_status()
   

   Step-by-step guide:

   1. Discover the API: Use your PCAP analysis from the previous step. Look for HTTP POST/GET requests to internal paths like `/api/start` or /cgi-bin/luci.
   2. Map Endpoints: Note the structure of the requests—the URL, parameters, and JSON payloads. Tools like `curl` can be used to manually replicate these calls.
   3. Handle Authentication: The script may need to include a token or use a specific header. This can sometimes be hardcoded in the device's firmware or extracted from the official app.
   4. Script the Actions: Write Python functions using the `requests` library for each action you want to perform (start, stop, dock, status).

   5. Hardening the Device: Changing Defaults and Disabling Services
      Regaining control is only half the battle; securing the device against future manufacturer interference or other threats is critical.

   Verified Linux Command List (run on the device via UART):

    1. Change the root password on the device
   passwd
   
   <ol>
   <li>Kill the manufacturer's remote management daemon
   ps | grep mgmt_daemon | grep -v grep | awk '{print $1}' | xargs kill -9</p></li>
   <li><p>Move the daemon's binary to back it up and prevent it from starting
   mv /usr/bin/mgmt_daemon /usr/bin/mgmt_daemon.bak</p></li>
   <li><p>Make the filesystem read-only to prevent changes (if supported)
   mount -o remount,ro /</p></li>
   <li><p>Check and disable unnecessary startup services
   cat /etc/inittab
   ls /etc/rc.d/</p></li>
   <li><p>Remove or block the manufacturer's public key from SSH authorized_keys
   rm /etc/dropbear/authorized_keys