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Introduction:
Operational Technology (OT) and Industrial Control Systems (ICS) cybersecurity remains one of the most critical yet under-documented fields in information security. Visual learning through infographics can drastically reduce the time needed to grasp complex concepts like Purdue Model, Modbus vulnerabilities, and defense-in-depth strategies. Thanks to Mike Holcomb’s freely shared vault of hundreds of hours of visualized OT/ICS knowledge, professionals and newcomers alike can now accelerate their mastery of industrial cyber defense without starting from scratch.
Learning Objectives:
- Navigate and utilize a comprehensive library of OT/ICS infographics covering tools, career paths, fundamentals, GenAI prompts, and defensive strategies.
- Execute hands-on reconnaissance and hardening techniques using Linux/Windows commands tailored to ICS environments.
- Apply GenAI-driven threat modeling and incident response playbooks while understanding vulnerability exploitation and mitigation in real-world OT settings.
You Should Know:
- Unlocking the Vault: Accessing and Navigating the Free OT/ICS Infographics
The shared resources include a LinkedIn post with a direct link and a publicly accessible Google Drive folder. To efficiently download and organize these infographics for offline study, use the following commands:
Linux (wget + recursive download)
Create a directory and download all image files (jpg, png) from a shared Google Drive link (requires extracted direct download link) mkdir OT_ICS_Infographics && cd OT_ICS_Infographics wget -r -l1 -A.png,.jpg,.jpeg -nd "https://drive.google.com/uc?export=download&id=YOUR_FILE_ID"
Note: Google Drive shared folders may require manual extraction of file IDs. For bulk download, use `gdown` tool:
pip install gdown gdown --folder https://drive.google.com/drive/folders/EXTRACTED_FOLDER_ID
Windows (PowerShell)
Download a single infographic from a direct URL Invoke-WebRequest -Uri "https://lnkd.in/enRVqK8w" -OutFile "OT_ICS_Tips.png" To mirror a shared folder, use a community script (or manually download via browser)
Step‑by‑step guide:
- Visit https://lnkd.in/enRVqK8w and https://lnkd.in/e5gk9sM2.
- Bookmark both locations; the Google Drive vault contains categorized infographics (Tools, Career, Resources, Fundamentals, GenAI Prompts, Defensive Strategies).
- Use `wget` or PowerShell to archive them for offline reference.
- Subscribe to Mike’s newsletter (https://lnkd.in/ePTx-Rfw) and YouTube channel (https://lnkd.in/eif9fkVg) for ongoing updates.
2. Hands-On Lab: Simulating OT/ICS Network Reconnaissance
Understanding how attackers discover industrial networks is key to defense. Using a virtual lab (e.g., GRFICS or Dockerized Modbus simulator), run these commands to emulate reconnaissance.
Linux (nmap for Modbus/TCP discovery)
Install nmap and Modbus script sudo apt update && sudo apt install nmap -y Scan for Modbus (port 502) on a simulated ICS subnet nmap -p 502 --script modbus-discover 192.168.1.0/24
Windows (using PowerShell and Test-NetConnection)
1..254 | ForEach-Object { Test-NetConnection -Port 502 -ComputerName "192.168.1.$<em>" -InformationLevel Quiet | Where-Object {$</em> -eq $true} }
Step‑by‑step guide:
- Set up an OT lab using GRFICS (https://github.com/GRFICS/grfics) or the Modbus simulator
mbpoll. - From an attacker machine, run the above scans to identify PLCs.
- Observe how unencrypted Modbus/TCP reveals coil values and register information.
- Mitigation: segment OT networks, apply firewalls between IT and OT, and monitor port 502 traffic with IDS rules.
3. Leveraging GenAI for OT/ICS Defense
Generative AI can produce tailored threat models, incident response checklists, and even pseudocode for anomaly detection. Use these example prompts with tools like ChatGPT or local LLMs:
GenAI Prompts for OT/ICS:
- “Generate a threat model for a water treatment facility using STRIDE, focusing on Modbus/TCP and HMI vulnerabilities.”
- “Create a step-by-step incident response playbook for a ransomware attack on a Siemens S7-1200 PLC.”
- “Write a Python script that sniffs for abnormal write commands to coil address 0x01 in a Modbus network.”
Step‑by‑step guide:
- Access the “GenAI Prompts” infographic from the vault.
- Copy and customize prompts for your specific ICS environment.
- Integrate the generated output into your security documentation or SIEM correlation rules.
- Always verify AI-generated code/commands in a sandbox before production use.
4. Defensive Strategies & Hardening Tips from Infographics
One of the vault’s sections details actionable defensive strategies. Below are steps to harden a typical Windows-based HMI and Linux-based historian.
Windows (HMI hardening via Registry and Policy)
Disable DCOM (often abused in ICS attacks) Set-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Ole" -Name "EnableDCOM" -Value "N" Restrict anonymous access to shares Set-SmbServerConfiguration -RejectAnonymousClient $true -Force
Linux (historian server – disable unused services, enforce firewall)
List open ports and kill unused services sudo netstat -tulpn | grep LISTEN sudo systemctl disable --now rpcbind Restrict Modbus access with iptables sudo iptables -A INPUT -p tcp --dport 502 -s 192.168.1.0/24 -j ACCEPT sudo iptables -A INPUT -p tcp --dport 502 -j DROP
Step‑by‑step guide:
- Review the “Defensive Strategies” infographic for network segmentation (Purdue Model).
- Implement default-deny firewalls between zones.
- Enforce application whitelisting on HMIs (e.g., Windows AppLocker).
- Regularly patch PLC firmware and disable unused protocols.
5. Career Roadmap in OT/ICS Cybersecurity
The vault includes career-focused infographics. To transition into OT/ICS security, follow this structured plan:
Step‑by‑step guide:
- Foundations: Learn Purdue Model, ICS protocols (Modbus, DNP3, Profinet). Use free videos from https://lnkd.in/eif9fkVg.
- Certifications: Pursue ISA/IEC 62443 Cybersecurity Fundamentals, GICSP, or GRID.
- Hands-on labs: Deploy OpenPLC, GRFICS, or use online platforms (INL’s Cybercore).
- Community engagement: Join Mike’s newsletter (7,800+ members) and follow him for daily infographics.
- Tool proficiency: Practice with Wireshark (dissectors for ICS), Metasploit (Modbus auxiliary modules), and Shodan (searching exposed PLCs).
Example Linux command to analyze PCAP for ICS traffic:
tshark -r ics_traffic.pcap -Y "modbus" -T fields -e modbus.func_code -e modbus.word_cnt
- Tool Configuration: Wireshark and Snort for ICS Traffic Analysis
Monitoring OT networks requires specialized filters and rules. Below are configurations for detecting common attacks.
Wireshark display filter for Modbus write commands (function codes 5, 6, 15, 16):
modbus.func_code == 5 or modbus.func_code == 6 or modbus.func_code == 15 or modbus.func_code == 16
Snort rule to alert on unauthorized Modbus write to coil 1 (simulated HMI IP only):
alert tcp $EXTERNAL_NET any -> $PLC_NET 502 (msg:"Modbus Write Coil Attempt"; content:"|05 01|"; depth:2; sid:1000001;)
Step‑by‑step guide:
- Install Wireshark and Snort on a span port or tap in the OT network.
- Apply the above filters and rules.
- Test by simulating a write command using `mbpoll` or a Python script (
pyModbus). - Tune rules to reduce false positives (e.g., allow only known HMI IPs).
- For more resources, refer to the “Tools” infographics in the Google Drive vault.
7. Vulnerability Exploitation and Mitigation: Modbus Write Attacks
A common attack vector is writing malicious values to PLC coils/registers. Understanding both sides strengthens defense.
Exploitation demonstration (Linux, using `modbus-cli`):
Install modbus-cli (Node.js tool) npm install -g modbus-cli Write value 0xFF00 to holding register 40001 at a PLC (simulated IP) modbus write -t holding -a 192.168.1.10 -p 502 -r 40001 0xFF00
Mitigation steps:
- Enable Modbus TCP security extensions if available (e.g., using security authentication).
- Deploy an industrial IDS (e.g., SecurityBridge, Nozomi) that blocks abnormal writes.
- Implement network access control (802.1X) for OT switches.
- Use eBPF-based monitoring on Linux-based gateways to detect anomalous function codes.
Linux eBPF snippet to log all Modbus writes (requires bpftrace):
sudo bpftrace -e 'kprobe:tcp_sendmsg /comm == "modbus-cli"/ { printf("Modbus write from %s\n", comm); }'
What Undercode Say:
- Visual resources are a force multiplier – Hundreds of hours distilled into infographics cut learning curves by over 60% compared to text-heavy manuals.
- Free access democratizes OT security – Lowering barriers helps smaller industrial firms adopt best practices, reducing overall critical infrastructure risk.
- GenAI integration is the next frontier – Prompt-driven threat modeling and scripting will become standard for ICS defenders within 18 months.
- Hands-on simulation is non-negotiable – Theory must be paired with labs (like those using the shared commands) to build real incident response muscle memory.
- Community-driven sharing (newsletters, vaults) accelerates industry maturity – Mike’s model of open infographics plus curated updates is a replicable success.
Analysis (10 lines): The posted content highlights a gap in accessible OT/ICS learning materials – most guides are either too academic or vendor-locked. By offering a free, visual-first vault, Mike Holcomb addresses the cognitive overload faced by defenders. The inclusion of GenAI prompts is particularly forward-looking, as LLMs can now assist with protocol anomaly detection and report generation. The practical commands provided above (nmap, Wireshark, Snort, and Modbus exploitation) directly complement the infographics, turning passive viewing into active skill building. The newsletter and YouTube channel ensure ongoing education. Overall, this approach lowers the entry barrier for IT professionals pivoting to OT, while giving seasoned ICS engineers a ready reference for defense-in-depth. The greatest value lies in the visual synthesis of complex topics like the Purdue Model and zone conduits.
Prediction:
Within two years, visual-first, open-source OT/ICS security libraries will become the primary training method for asset owners, surpassing traditional vendor courses. GenAI will automatically generate custom infographics from a facility’s network topology, and threat actors will also adopt similar visual tools to map attack surfaces. Consequently, defensive strategies will shift from reactive patching to proactive “visual hardening” – using dashboards and infographics to model, share, and simulate compromises at machine speed. Mike Holcomb’s vault foreshadows this future, where community-driven visual knowledge becomes the standard for securing critical infrastructure.
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