OT & IT Convergence: Defending the Industrial Attack Surface in 2025

In 2025, the boundary between IT and operational technology (OT) is more porous than ever. What once were siloed environments are now deeply intertwined—creating new opportunities for efficiency, but also a vastly expanded attack surface. For industrial, manufacturing, energy, and critical infrastructure operators, the stakes are high: disruption in OT is real-world damage, not just data loss.

PLC

This article lays out the problem space, dissecting how adversaries move, where visibility fails, and what defense strategies are maturing in this fraught environment.


The Convergence Imperative — and Its Risks

What Is IT/OT Convergence?

IT/OT convergence is the process of integrating information systems (e.g. ERP, MES, analytics, control dashboards) with OT systems (e.g. SCADA, DCS, PLCs, RTUs). The goal: unify data flows, enable predictive maintenance, real-time monitoring, control logic feedback loops, operational analytics, and better asset management.

Yet, as IT and OT merge, their worlds’ assumptions—availability, safety, patch cycles, threat models—collide. OT demands always-on control; IT is optimized for data confidentiality and dynamic architecture. Bridging the two without opening the gates to compromise is the core challenge.

Why 2025 Is Different (and Dangerous)

  • Attacks are physical now. The 2025 Waterfall Threat Report shows a dramatic rise in attacks with physical consequences—shut-downs, equipment damage, lost output. Waterfall Security Solutions

  • Ransomware and state actors converge on OT. OT environments are now a primary target for adversaries aiming for disruption, not just data theft. zeronetworks.com+2Industrial Cyber+2

  • Device proliferation, blind spots. The explosion of IIoT/OT-connected sensors and actuators means incremental exposures mount. Nexus+2IAEE+2

  • Legacy systems with little guardrails. Many OT systems were never built with security in mind; patching is difficult or impossible. SSH+2Industrial Cyber+2

  • Stronger regulation and visibility demands. Critical infrastructure sectors face growing pressure—and liability—for cyber resilience. Honeywell+2Fortinet+2

  • Maturing defenders. Some organizations are already reducing attack frequency through segmentation, threat intelligence, and leadership-driven strategies. Fortinet


Attack Flow: From IT to OT — How the Adversary Moves

Understanding attacker paths is key to defending the convergence.

  1. Initial foothold in IT. Phishing, vulnerabilities, supply chain, remote access are typical vectors.

  2. Lateral movement toward bridging zones. Jump servers, VPNs, misconfigured proxies, flat networks let attackers pivot. Industrial Cyber+2zeronetworks.com+2

  3. Transit through DMZ / industrial demilitarized zones. Poorly controlled conduits allow protocol bridging, data transfer, or command injection. iotsecurityinstitute.com+2Palo Alto Networks+2

  4. Exploit OT protocols and logic. Once in the OT zone, attackers abuse weak or proprietary protocols (Modbus, EtherNet/IP, S7, etc.), manipulate command logic, disable safety interlocks. arXiv+2iotsecurityinstitute.com+2

  5. Physical disruption or sabotage. Alter sensor thresholds, open valves, shut down systems, or destroy equipment.

Because OT environments often have weaker monitoring and fewer detection controls, malicious actions may go unnoticed until damage occurs.


The Visibility & Inventory Gap

You can’t protect what you can’t see.

  • Publicly exposed OT devices number in the tens of thousands globally—many running legacy firmware with known critical vulnerabilities. arXiv

  • Some organizations report only minimal visibility into OT activity within central security operations. Nasstar

  • Legacy or proprietary protocols (e.g. serial, Modbus, nonstandard encodings) resist detection by standard IT tools.

  • Asset inventories are often stale, manual, or incomplete.

  • Patch lifecycle data, firmware versions, configuration drift are poorly tracked in OT systems.

Bridging that visibility gap is a precondition for any robust defense in the converged world.


Architectural Controls: Segmentation, Microperimeters & Zero Trust for OT

You must treat OT not as a static, trusted zone but as a layered, zero-trust-aware domain.

1. Zone & Conduit Model

Apply segmentation by functional zones (process control, supervisory, DMZ, enterprise) and use controlled conduits for traffic. This limits blast radius. iotsecurityinstitute.com+2Palo Alto Networks+2

2. Microperimeters & Microsegmentation

Within a zone, restrict east-west traffic. Only permit communications justified by policy and process. Use software-defined controls or enforcement at gateway devices.

3. Zero Trust Principles for OT

  • Least privilege access: Human, service, and device accounts should only have the rights they need to perform tasks. iotsecurityinstitute.com+1

  • Continuous verification: Authenticate and revalidate sessions, devices, and commands.

  • Context-based access: Enforce access based on time, behavior, process state, operational context.

  • Secure access overlays: Replace jump boxes and VPNs with secure, isolated access conduits that broker access rather than exposing direct paths. Industrial Cyber+1

4. Isolation & Filtering of Protocols

Deep understanding of OT protocols is required to permit or deny specific commands or fields. Use protocol-aware firewalls or DPI (deep packet inspection) for industrial protocols.

5. Redundancy & Fail-Safe Paths

Architect fallback paths and redundancy such that the failure of a security component doesn’t cascade into OT downtime.


Detection & Response in OT Environments

Because OT environments are often low-change, anomaly-based detection is especially valuable.

Anomaly & Behavioral Monitoring

Use models of normal process behavior, network traffic baselines, and device state transitions to detect deviations. This approach catches zero-days and novel attacks that signature tools miss. Nozomi Networks+2zeronetworks.com+2

Protocol-Aware Monitoring

Deep inspection of industrial protocols (Modbus, DNP3, EtherNet/IP, S7) lets you detect invalid or dangerous commands (e.g. disabling PLC logic, spoofing commands).

Hybrid IT/OT SOCs & Playbooks

Forging a unified operations center that spans IT and OT (or tightly coordinates) is vital. Incident playbooks should understand process impact, safe rollback paths, and physical fallback strategies.

Response & Containment

  • Quarantine zones or devices quickly.

  • Use “safe shutdown” logic rather than blunt kill switches.

  • Leverage automated rollback or fail-safe states.

  • Ensure forensic capture of device commands and logs for post-mortem.


Patch, Maintenance & Change in OT Environments

Patching is thorny in OT—disrupting uptime or control logic can have dire consequences. But ignoring vulnerabilities is not viable either.

Risk-Based Patch Prioritization

Prioritize based on:

  1. Criticality of the device (safety, control, reliability).

  2. Exposure (whether reachable from IT or remote networks).

  3. Known exploitability and threat context.

Scheduled Windows & Safe Rollouts

Use maintenance windows, laboratory testing, staged rollouts, and fallback plans to apply patches in controlled fashion.

Virtual Patching / Compensating Controls

Where direct patching is impractical, employ compensating controls—firewall rules, filtering, command-level controls, or wrappers that mediate traffic.

Vendor Coordination & Secure Updates

Work with vendors for safe update mechanisms, integrity verification, rollback capability, and cryptographic signing of firmware.

Configuration Lockdown & Hardening

Disable unused services, remove default accounts, enforce least privilege controls, and lock down configuration interfaces. Industrial Cyber


Operating in Hybrid Environments: Best Practices & Pitfalls

  • Journeys, not Big Bangs. Start with a pilot cell or site; mature gradually.

  • Cross-domain teams. Build integrated IT/OT guardrails teams; train OT engineers with security awareness and IT folk with process sensitivity. iotsecurityinstitute.com+2Secomea+2

  • Change management & governance. Formal processes must span both domains, with risk acceptance, escalation, and rollback capabilities.

  • Security debt awareness. Legacy systems will always exist; plan compensating controls, migration paths, or compensating wrappers.

  • Simulation & digital twins. Use testbeds or digital twins to validate security changes before deployment.

  • Supply chain & third-party access. Strong control over third-party remote access is essential—no direct device access unless brokered and constrained. Industrial Cyber+2zeronetworks.com+2


Governance, Compliance & Regulatory Alignment

  • Map your security controls to frameworks such as ISA/IEC 62443NIST SP 800‑82, and relevant national ICS/OT guidelines. iotsecurityinstitute.com+2Tenable®+2

  • Develop risk governance that includes process safety, availability, and cybersecurity in tandem.

  • Align with critical infrastructure regulation (e.g. NIS2 in Europe, SEC cyber rules, local ICS/OT mandates). Honeywell+1

  • Build executive visibility and metrics (mean time to containment, blast radius, safety impact) to support prioritization.


Roadmap: From Zero → Maturity

Here’s a rough maturation path you might use:

Phase Focus Key Activities
Pilot / Awareness Reduce risk in one zone Map asset inventory, segment pilot cell, deploy detection sensors
Hardening & Control Extend structural defenses Enforce microperimeters, apply least privilege, protocol filtering
Detection & Response Build visibility & control Anomaly detection, OT-aware monitoring, SOC integration
Patching & Maintenance Improve security hygiene Risk-based patching, vendor collaboration, configuration lockdown
Scale & Governance Expand and formalize Extend to all zones, incident playbooks, governance models, metrics, compliance
Continuous Optimization Adapt & refine Threat intelligence feedback, lessons learned, iterative improvements

Start small, show value, then scale incrementally—don’t try to boil the ocean in one leap.


Use Case Scenarios

  1. Remote Maintenance Abuse
    A vendor’s remote access via a jump host is compromised. The attacker uses that jump host to send commands to PLCs via an unfiltered conduit, shutting down a production line.

  2. Logic Tampering via Protocol Abuse
    An attacker intercepts commands over EtherNet/IP and alters setpoints on a pressure sensor—causing shock pressure and damaging equipment before operators notice.

  3. Firmware Exploit on Legacy Device
    A field RTU is running firmware with a known remote vulnerability. The attacker exploits that, gains control, and uses it as a pivot point deeper into OT.

  4. Lateral Movement from IT
    A phishing campaign generates a foothold on IT. The attacker escalates privileges, accesses the central historian, and from there reaches into OT DMZ and onward.

Each scenario highlights the need for segmentation, detection, and disciplined control at each boundary.


Checklist & Practical Guidance

  • ⚙️ Inventory & visibility: Map all OT/IIoT devices, asset data, communications, and protocols.

  • 🔒 Zone & micro‑segment: Enforce strict controls around process, supervisory, and enterprise connectivity.

  • ✅ Least privilege and zero trust: Limit access to the minimal set of rights, revalidate often.

  • 📡 Protocol filtering: Use deep packet inspection to validate or block unsafe commands.

  • 💡 Anomaly detection: Use behavioral models, baselining, and alerts on deviations.

  • 🛠 Patching strategy: Risk-based prioritization, scheduled windows, fallback planning.

  • 🧷 Hardening & configuration control: Remove unused services, lock down interfaces, enforce secure defaults.

  • 🔀 Incident playbooks: Include safe rollback, forensic capture, containment paths.

  • 👥 Cross-functional teams: Co-locate or synchronize OT, IT, security, operations staff.

  • 📈 Metrics & executive reporting: Use security KPIs contextualized to safety, availability, and damage containment.

  • 🔄 Continuous review & iteration: Ingest lessons learned, threat intelligence, and adapt.

  • 📜 Framework alignment: Use ISA/IEC 62443, NIST 800‑82, or sector-specific guidelines.


Final Thoughts

As of 2025, you can’t treat OT as a passive, hidden domain. The convergence is inevitable—and attackers know it. The good news is that mature defense strategies are emerging: segmentation, zero trust, anomaly-based detection, and governance-focused integration.

The path forward is not about plugging every hole at once. It’s about building layered defenses, prioritizing by criticality, and evolving your posture incrementally. In a world where a successful exploit can physically damage infrastructure or disrupt a grid, the resilience you build today may be your strongest asset tomorrow.

More Info and Assistance

For discussion, more information, or assistance, please contact us. (614) 351-1237 will get us on the phone, and info@microsolved.com will get us via email. Reach out to schedule a no-hassle and no-pressure discussion. Put out 30+ years of OT experience to work for you! 

 

 

* AI tools were used as a research assistant for this content, but human moderation and writing are also included. The included images are AI-generated.

Why You Should Support CS2AI

What is Control Systems Cyber Security Association International (CS2AI.org)?

The mission of the Control Systems Cyber Security Association, Inc. (CS2AI) is to promote and advance cyber security education, research, and practice to protect critical infrastructure and ensure the safety and reliability of our nation’s control systems.

What does that mean? It means we are here to help you understand how to keep your control system safe from hackers, malware, and other threats. We want to ensure you know what to look for in a good cybersecurity program and how to find it.

We also want to ensure you have access to the best resources available to help you stay up-to-date on current trends and technologies.

Why does MSI support it?

Because we believe in its mission. We believe in making sure everyone has access to the information they need to make informed decisions about their own cybersecurity programs, especially when it comes to ICS.

We believe in helping people learn more about cybersecurity so they can take steps toward protecting themselves and their organizations.

We believe in supporting those who share our passion for improving the world through technology. CS2AI supports the core mission of MSI – making the online world a safer place for all of us.

How do I get involved?

It’s simple – click here to learn more about joining and the benefits of supporting the ongoing efforts to improve global cyber security.

Why Emulate a PLC with a Raspberry Pi

One of the most powerful uses of emulating a PLC (Programmable Logic Controller) field device with a Raspberry Pi is that it provides an affordable and easily obtained platform for prototyping, performing ladder logic testing, and researching various industrial control systems and cybersecurity concepts.

Raspberry Pis are Affordable

Raspberry Pi models 3 and 4 are significantly more affordable than real PLCs. A typical PLC can cost hundreds or thousands of dollars.

The Raspberry Pi costs around $35-50 depending on your model choice. This makes them very accessible to hobbyists, students, researchers, developers, and anyone else who wants to work with the basics of industrial control systems. The low cost makes them ideal candidates to emulate a PLC in many scenarios.

Raspberry Pis are Easily Obtainable

PLCs can be quite difficult to come by, especially if you want one without any pre-existing software installed. Many manufacturers will not sell their products to third parties unless they have some kind of existing relationship. If you don’t already know someone at the manufacturer then you may need to pay a hefty upcharge. Additionally, purchasing the addons for power supplies, specific programming software, and such can quickly turn into a slog of paperwork and supporting tasks. The lead time and delivery times can take weeks to months.

The Raspberry Pi, on the other hand, can be purchased at many big-box electronics or computer stores, directly from many providers, or even delivered to your door from Amazon and other online sources. It uses a common USB power supply and can be configured and programmed using open source tools available online. Lead time is a couple of days to a few hours, letting you stay focused on your work.

The OpenPLC Project

The OpenPLC Project is a stable, well-documented toolkit for emulating basic PLC operations on the Pi. It has been used successfully to simulate a variety of different types of PLCs and includes support for ladder logic and other common PLC functions. You can find the programming reference and review the available capabilities here.

You can get OpenPLC up and running on a Pi in less than 30 minutes. In our testing, we were able to begin using the emulated PLC in our lab within an hour!

Going The Extra Mile With SCADABR

SCADABR is an open-source supervisory control and data acquisition software package designed to allow you to create interactive screens or human-machine interfaces (HMI) for your automation projects. It provides tools for creating graphical user interface widgets, event handlers, timers, and dialogs. With its ability to communicate with multiple controllers (including OpenPLC), ScadaBR is an ideal companion for the OpenPLC Runtime and Editor.

Using a Pi, OpenPLC, and SCADABR together, can get you a very powerful and useful PLC platform up and running for under $100 and in less than a few hours. Once implemented, you can use the platform to learn about industrial controls systems, ladder logic, PLC programming, and operations. You can also do basic ladder logic research and testing, and even prototyping for future real-world PLC deployments. Cybersecurity folks also have a very capable platform for learning about industrial control security requirements, performing vulnerability research, reverse engineering, or practicing their assessment skills in a safe environment.

While you might not get the full power of a true PLC (there are some limitations to Pi’s capabilities), you will likely get more than you expect. If you have an interest in or a need for some basic industrial control systems capabilities, this is a great place to start.

 

 

ICS/SCADA Security Symposium 2014 Announced

For those of you who were wondering about our yearly event, the 4th annual ICS/SCADA Security Symposium has been announced!

The date will be Thursday, December 11, 2014 and the entire event will be virtual! Yes, that’s right, no travel & no scheduling people to cover the control room. YOU can learn from right there! 

To learn more about the event, the schedule and to register, click here!

Save The Date: 2014 ICS/SCADA Security Symposium Dec. 11

This year’s ICS/SCADA Security Symposium will be held on Thursday, December 11, 2014. This year’s event will be a little different, in that we are opening it up to any organizations who are asset owners or manufacturers of ICS/SCADA components. That includes utilities, manufacturing companies, pharma, etc. If you are interested in ICS security, you can sign up for the event.

This year’s event will also be virtual. It will be a series of Webinars held on the same day in 45 minute blocks, with time for follow-on questions. We will also hold a Twitter Q&A Hour from 1pm – 2pm Eastern, and we will attempt to make all speakers available for the Q&A!

In addition, we plan to stand up a supporting website for the event, and release a number of materials, including podcasts, interviews and other surprises the day of the event!

We will be tracking attendance in the webinars and providing notes of attestation for attendees for the purpose of CPE credits. We hope this new format will allow folks who wanted to attend in the past, but either couldn’t make the physical trip to Columbus or couldn’t leave their positions to attend training the ability to join us.

More details, including speakers and topics, as well as schedules, hashtags and other info will be released shortly. Thanks for reading, and we hope to see you on 12/11/14!

Co-Op & Municipal Utilities Get Discounts in July

Attention Co-Op & Municipal utilities — MSI is offering discounts to your organizations on professional services (policy/process, assessments, pen-testing, etc.), lab services (device & AMR/AMI assessments, threat assessments, etc.) and HoneyPoint Security Server for the month of July. Book the business before July 31’st and have the work/implementation completed before December 31st of 2014 and you receive a discount up to 30% off!

Do you need pen-testing against your business network? Need web app assessments on billing or payment systems? Have a call for risk assessments, smart grid device testing or fraud testing against your meters and field gear? All of this and more qualifies!

Check out our ICS/SCADA specific services by clicking here!

Give Allan Bergen a call today at 513-300-0194 to learn more about our program. We truly appreciate the hard work and dedication that Co-op and Municipal utility teams do, and we look forward to working with you! 

Brent Huston to Lead ICS/SCADA Honeypot Webinar with SANS

Our Founder and CEO, Brent Huston (@lbhuston) will be leading a SANS webinar on ICS/SCADA honeypots. The webinar is scheduled for November, 25th, 2013 and you can find more information and register by visiting this page.

The webinar will cover when honeypots are and are not useful, basic deployment strategies and insights into using them for detection in field deployments and control environments. 

Check it out, tune in and give Brent a shout out on Twitter. Thanks for reading and we hope you enjoy the webinar.

Thanks for Making the 3rd Mid-West ICS/SCADA Security Symposium a Success

Thanks to the attendees and speakers who participated yesterday in the 3rd Annual ICS/SCADA Security Symposium. It was another great event and once again, the center of the value was in the interactions of the audience with the speakers and each other. It’s great to hear asset owners discuss what is working, what is challenging and what is critical in their minds.

Thanks again to those who attended and contributed to making this event such a wonderful thing again this year. We appreciate it and we can’t wait until next year to do it all again.

Thank YOU!

SANS ICS Summit & Training in Singapore

SANS Asia Pacific ICS Summit and Training 2013 – Singapore

If you have any responsibility for security of control systems – policy, engineering, governance or operations you won’t want to miss the Asia Pacific ICS Security Summit taking place 2-8 December 2013 where you will:

Learn all about the new Global ICS Professional Security Certification

Gain the most current information regarding Industrial Control System threats and learn how to best prepare to defend against them

Hear what works and what does not from peer organizations. 

Network with top individuals in the field of Industrial Control Systems security and return from the Summit with solutions you can immediately put to use in your organization. 

Listen to 15+ speakers from a variety of companies who will cover exceptional content throughout the two-day Summit.

Earn CPE credits for the summit and course you attend

 

ICS410: ICS Cyber Security Essentials, (Brand New course) – 4-8 December taught by SANS Faculty Fellow Dr. Eric Cole will provide a standardized foundational set of skills, knowledge and abilities for Industrial Cyber Security professionals. This course is designed to ensure that the workforce involved in supporting and defending Industrial Control Systems is trained to perform work in a manner that will keep the operational environment safe, secure and resilient against current and emerging cyber threats.

Agenda highlights for the summit include:

A Community Approach to Securing the Cyberspace to Enhance National Resilience

The Good, Bad and the Ugly: Certification of People, Processes and Devices 

SCADA Security Assessment Methodology: The Malaysia Experience  

The State of Critical Control System Security in Japan 

Smart Security : Strengthening Information Protection in Your ICS

 

To learn more about the Summit and Training, or register now and save 5% on your registration with code SANSICS_MSI5, please visit: http://www.sans.org/info/142537