Securing Your OT with a Limited Budget: 5 High-Impact, Low-Cost Steps

Let’s be honest: securing Operational Technology (OT) environments is hard enough when you have a healthy cybersecurity budget. But what happens when you're operating under tight financial constraints—a reality for many mid-sized manufacturers, utility operators, and process industries, especially in emerging economies such as India and the UAE?

The stakes are certainly high. A ransomware attack on a programmable logic controller (PLC) doesn’t just mean downtime—it could mean halted production, slippage of commitments, physical damage, environmental hazards, and loss of life.

So, what do you do when you’re expected to protect the critical core of your operations with relatively little funding? The answer lies in 3 words-- prioritization, smart frameworks, and tactical focus.

Based on real-world fieldwork, lessons from the IEC 62443 series, and years of working with energy, oil and gas, and manufacturing clients, here are 5 high-impact, low-cost steps that can significantly enhance your OT security posture—even when operating on a tight budget.

Step 1: Start with a basic IEC 62443-based risk assessment

You don’t need to pay big consulting dollars to begin understanding your risk.

Why it matters:

The IEC 62443 standard is the globally accepted framework for securing industrial control systems. It guides you in identifying critical assets, understanding zones and conduits, and defining Security Levels (SLs) based on risk.

How to do it on a tight budget:

Asset Inventory: Use free or low-cost passive network discovery tools to identify your ICS components. Map out PLCs, HMIs, SCADA servers, and network switches.
Zone and Conduit Modelling: Group your assets into logical zones (e.g., control zone, DMZ, enterprise zone) and map data flows between them. Even a Visio diagram or a whiteboard session can suffice.
Risk Ranking: For each zone, evaluate the impact of compromise (safety, downtime, cost). You don’t need quantitative models—qualitative ranking (High/Medium/Low) is fine to start.

Outcome: You’ll know which assets and zones are “crown jewels” and which areas pose the greatest risk, letting you focus your limited resources where they matter most.

Step 2: Train the people who interact with OT systems every day

You can’t secure what your people don't understand. And yet, most OT personnel—from plant engineers to control room technicians—still view cybersecurity as an IT problem.

Why it matters

In OT, humans are often the weakest (or strongest) link. A well-meaning technician connecting a laptop with outdated firmware to a switch can create an instant vulnerability. We have also seen how mobile hotspots and usb drives are liberally used in critical infrastructure.

Low-cost training methods:

Host brown-bag sessions or toolbox talks: Teach your teams how attackers gain access, and why USBs, remote access, or default passwords are high-risk.
Gamify awareness: Set up a simple challenge—e.g., “spot the phishing email,” or “find what’s wrong with this network diagram.” Offer a small prize.
Use free resources: Organizations like ISA, US-CERT, and NCIIPC (India) offer excellent public guides and awareness materials.
Outcome: Better security hygiene at the front lines without spending on expensive training programs.

Step 3: Create a governance and policy framework - even a simple one will do

“Governance” sounds corporate and expensive. But it doesn’t have to be. You just need a clear structure for decision-making, accountability, and documentation.

Why it matters

Without a framework, even the best technical controls fall apart. Who approves remote access? Who maintains the asset inventory? Who reports incidents?

What should it cover?

Appoint an OT Security Coordinator: This doesn't have to be a full-time role. Assign someone with both plant and security knowledge.
Define Acceptable Use and Remote Access Policies: Clearly document what’s allowed and what’s not, especially for contractors and vendors.
Maintain a Central Policy Binder: Store simple policies (access control, patching frequency, backup strategy, USB use, etc.) in one place, digitally or physically.

Use templates based on IEC 62443-2-1 (“Security program requirements for IACS asset owners”)—these provide structure without requiring custom development. [Request one from Shieldworkz if you haven’t got a copy already]

Outcome: A basic governance framework shows auditors and management that you’re serious—even if you’re just starting out.

Step 4: Build a lightweight incident response plan

Cyber incidents in OT don’t need to be sophisticated to be disruptive. A misconfigured router or a malicious spreadsheet macro on an HMI workstation can shut down operations.

Why it matters:

If your team doesn’t know how to respond, who to call, what to isolate, what evidence to collect—the impact multiplies. Having a plan doesn’t cost much, but not having one can cost everything.

How to do it smartly:

Define clear escalation paths: Who responds first? Who communicates with the management? How will incidents be graded? With external agencies like CERT-In or NCIIPC?
Create a “first 30 minutes” playbook: What should operators do if they suspect ransomware or network anomalies?
Run tabletop exercises: Once a quarter, run a mock scenario: “A SCADA server goes down. What now?” Discuss the steps, not just the outcomes.
Log everything: Even basic Windows logs or switch logs can be a lifesaver post-incident. Centralize where you can.

Outcome: You won’t eliminate incidents, but you’ll reduce their damage, cost, and time to recovery, making your limited resources go further.

Step 5: Segment, isolate, and monitor, using what you already have

Network segmentation is one of the most effective OT security controls, and you don’t need fancy micro-segmentation platforms to begin.

Why it matters:

Most OT breaches happen when attackers move laterally from IT into OT, or from one OT zone into another. Segmentation limits that movement.

Practical actions:

Use existing firewalls: Many plants already have firewalls between IT and OT but haven’t configured them well. Use access control lists (ACLs) to restrict non-essential traffic.
Establish read-only DMZs: Where possible, use a demilitarized zone between IT and OT to route data (e.g., historian or MES access).
Disable unused ports: On switches, routers, and endpoints, especially USBs and serial interfaces.
Monitor passively: Use RoI-focused tools such as Shieldworkz for network visibility and network detection and response. You don’t need deep packet inspection on day one.

Start small: Even a basic rule like “no internet access from the control zone” dramatically reduces risk.

Outcome: You make lateral movement harder for attackers, without needing to overhaul your entire network architecture.

So, what does this like in a real world?

Let’s say you’re a mid-sized power company in western India. You have:

3 remote sites with SCADA,
Limited budget,
1 firewall between IT and OT,
No formal security policy.

In under 90 days, and with almost no capex, you could:

Identify all PLCs and network zones using a simple mapping exercise.
Conduct IEC 62443-style risk ranking to focus protection on gas flow controllers.
Appoint your senior plant engineer as OT security point-of-contact.
Create a 2-page IR plan and run a drill with 5 staff.
Block USB ports on SCADA HMIs and tighten firewall rules.
Train all employees that manage or deal with OT
Figured out additional security measures for your core systems

The result? You have reduced your overall risk exposure by 47 percent—and given your board the confidence that you’re not flying blind. Such an effort could also serve as a strong foundation for an enterprise-wide OT security program.

Talk to Shieldworkz OT security experts to learn more about securing your CPS infrastructure.

Book an IEC 62443-based risk assessment for your enterprise.