OT / ICS Security

Operational technology (OT) and industrial control systems run factories, power, water and buildings. Security here protects safety and uptime, not only data. This roadmap suits IT security staff moving into OT. Networking basics are needed.

• Understand basic networking
• Learn the safety-first mindset of OT
• Plan your study time

• CyberA4U Academy — courses

OT prioritizes safety and availability over confidentiality, runs decades-old systems, and can't simply be patched or rebooted. NIST SP 800-82 explains these differences.

• Compare IT and OT priorities
• Understand long lifecycles and legacy systems
• Respect safety constraints

Tools & tech: OT

• NIST SP 800-82 Rev. 3 — Guide to OT Security

The Purdue model describes OT networks in levels — from field devices to enterprise IT — and helps plan zones and conduits between them.

• Describe the Purdue levels
• Identify where the IT/OT boundary sits
• Use zones and conduits for segmentation

Tools & tech: OT

• NIST SP 800-82 Rev. 3 — Guide to OT Security

Many industrial protocols were designed without authentication or encryption. Knowing how they work helps you monitor and protect them.

• Explain Modbus, DNP3 and OPC UA at a high level
• Understand their security limitations
• Know which have secure variants

Tools & tech: OT

• Wireshark Wiki — Sample captures

ICS threats include ransomware spreading from IT, remote-access abuse and targeted attacks on controllers. MITRE ATT&CK for ICS catalogs these techniques.

• Describe major ICS threat categories
• Use ATT&CK for ICS
• Learn from public incident reports

Tools & tech: OT

Learn it on CyberA4U:Module 20: Connected Device and Industrial System Attacks

• MITRE ATT&CK for ICS

Segmentation between IT and OT, and within OT, is the most important control. Industrial DMZs and strict conduits limit what can reach controllers.

• Design IT/OT segmentation with an industrial DMZ
• Restrict conduits to required flows
• Document allowed communications

Tools & tech: OT

• NIST SP 800-82 Rev. 3 — Guide to OT Security

Vendor and remote access is a common entry point into OT. It must be controlled, monitored and time-limited.

• Use secure, brokered remote access
• Require MFA and approvals
• Monitor and record sessions

Tools & tech: OT

• CISA — Industrial Control Systems

OT networks are usually monitored passively — listening to traffic without touching fragile devices — to build asset inventories and detect anomalies.

• Understand passive vs active monitoring
• Build an asset inventory from traffic
• Detect unusual commands and new devices

Tools & tech: OT

• CISA — Industrial Control Systems

OT systems often can't be patched quickly because of certification, vendor support or uptime. Compensating controls reduce risk meanwhile.

• Prioritize OT patches by risk
• Coordinate with vendors and operations
• Use compensating controls

Tools & tech: OT

• NIST SP 800-82 Rev. 3 — Guide to OT Security

OT incident response must protect safety first and coordinate with engineers and operators before disconnecting anything.

• Include operations and safety roles in IR
• Plan safe isolation options
• Practice with OT-specific scenarios

Tools & tech: OT

• CISA Tabletop Exercise Packages

Industrial systems depend on vendors for software, firmware and support. Their security practices directly affect yours.

• Include security requirements in procurement
• Verify firmware and software integrity
• Track vendor advisories

Tools & tech: OT

• NIST SP 800-161 Rev. 1 — Cybersecurity Supply Chain Risk Management

ISA/IEC 62443 is the main standard family for industrial cybersecurity, complemented by NIST SP 800-82 and sector regulations.

• Understand the structure of ISA/IEC 62443
• Use security levels and zones
• Know relevant sector requirements

Tools & tech: OT

• ISA/IEC 62443 series of standards

Active scanning can crash fragile controllers. OT assessments rely on documentation, passive data and carefully coordinated, approved testing.

• Prefer passive and document-based assessment
• Coordinate any active testing with operations
• Test in labs or during maintenance windows

Tools & tech: OT

• NIST SP 800-82 Rev. 3 — Guide to OT Security

Check that you can explain OT risks and design practical, safety-aware protections.

• Design segmentation using Purdue levels
• Plan secure remote access and monitoring
• Adapt incident response for OT

• CyberA4U CTF Arena — practice challenges

You now understand OT/ICS security. Continue with IoT Security, Network Administrator or Incident Response, or look into ISA/IEC 62443 or GIAC GICSP certification.

• Keep following ICS advisories
• Choose your next roadmap
• Share a design write-up

• CyberA4U CTF Arena — practice challenges