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43. IoT and OT Security – Cameras, Smart Devices, Plant Networks

43.5 Network Segregation – IT / OT Zones, Jump Hosts, firewalld

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Flat LAN = camera compromise → billing DB. Blue pattern (Purdue-model idea, simplified for SME):

  1. IoT VLAN – cameras, MQTT sensors only
  2. OT VLAN – packing PLC / HMI (if you have a real plant lab later – still isolated)
  3. IT VLAN – office PCs, Raja's ERP
  4. Firewall between zones – default deny; allow only listed flows
  5. Jump host (bastion) for admins – MFA, logging, no direct RDP from internet to HMI
# Amazon Linux lab edge – example allow-list thinking (host-only demo IPs)
sudo yum install firewalld
sudo systemctl enable firewalld
sudo service firewalld start
sudo firewall-cmd --permanent --new-zone=iotlab
sudo firewall-cmd --permanent --zone=iotlab --add-source=192.168.56.50/32
# IoT VM may reach MQTT broker on .40:1883 only (lab); no forward to Metasploitable DB ideas
sudo firewall-cmd --permanent --zone=iotlab --add-rich-rule='rule family="ipv4" destination address="192.168.56.40" port port="1883" protocol="tcp" accept'
sudo firewall-cmd --reload
sudo firewall-cmd --list-all-zones

Ubuntu note: sudo apt install firewalld or use ufw with equal care – sudo service ufw status. Don't invent a second brain with both ufw and firewalld fighting.

Red team (attacker) does Blue team (defender) detects / stops
Lands on camera; scans .0/24 for 445/3306 VLAN + firewall inter-zone deny; alert on camera→DB flows
Phishes IT user; RDP straight to HMI Jump host only; no HMI on IT VLAN
Brings laptop into OT switch "for Wireshark" Port security / 802.1X ideas; change control

Ravindra Bagale's Tip

Students say "VLAN = secure" without any firewall rules. A VLAN without ACLs = a fancy colour on the same flood. Interview: show the zone + one allowed port. Got it?

Lab

Draw three clouds: IT / IoT / OT for Sahyadri Nashik. List five denied flows (camera→RDS, PLC→internet, laptop→Modbus). Optional: implement one rich rule on OWN .40.

Extended teaching notes

Why this lesson matters

Cameras, sensors and plant controllers often ship with weak defaults. Segment them from IT, change passwords, block inbound internet, and watch outbound traffic.

Real examples

Global: Mirai showed what default passwords on routers/cameras can do at scale. Indian SME (sample): a factory puts PLCs on a separate VLAN reachable only via a jump host.

Mini case study

Suppose we are on a purple-team exercise for an Indian mid-size company (sample data). Red notes a technique from this lesson against a lab clone. Blue must show the control that stops it, the log that would have fired, and the ticket that hardens production. That is the standard this course trains you for.

Defender's worksheet (do this today)

  1. Write the lesson title, date and the exact lab target you are allowed to use.
  2. List three owned systems (VMs, apps, or cloud accounts) where this lesson applies.
  3. Run one safe check from the lesson on a lab system only. Paste the command and output.
  4. Write a two-sentence fix you would give a teammate.
  5. Name one related public advisory (CERT-In, CISA, NVD, or a vendor bulletin) with its date.

Indian workplace (sample data)

Suppose we are a junior analyst at Infosys, TCS, Wipro or a fintech SOC in Bengaluru/Pune. Turn this lesson into one checklist item with an owner, a due date and a place to store evidence (ticket + screenshot).

Global practice

Compare your notes with OWASP, CIS Benchmarks, NIST CSF/IR guidance or a cloud Well-Architected security question. Write five lines on what overlaps.

Everyday analogy

Explain the risk and the fix to a family member without jargon. If they can repeat the warning, you understand it well enough to teach juniors.

Key terms

  • Control: a safeguard (patch, config, process, detection).
  • Finding: a weakness backed by evidence.
  • Remediation: the fix plus how you verified it.
  • Scope: systems you have written permission to touch.
  • Least privilege: only the access the task needs.
  • Defence in depth: several layers so one failure does not end the story.

Common mistakes

  • Skipping written permission "just for a quick scan".
  • Practising on hostel, office or public targets without authorisation.
  • Collecting tool output without writing the fix.
  • Copying attack steps onto production to "verify". Defenders verify with versions, configs and patches.
  • Publishing screenshots that contain secrets, cookies or internal hostnames.

Recap

  • Evidence, fix, owner, date.
  • Own lab only.
  • Fix > spectacle.