Remediation Guide
IEC 62443
Evidence-Backed OT Security Level Assessment
Bridging the Gap Between What You Claim and What You Can Actually Evidence
Most OT security assessments end with a slide deck. Yours should end with proof. If you are responsible for the cybersecurity of an industrial automation or control system - whether you are a CISO, OT Security Manager, internal auditor, or plant operations lead - you already know that regulatory pressure is mounting, threat actors are getting more sophisticated, and the gap between what your organization says it has and what it can actually evidence is often wider than anyone wants to admit. That gap is exactly what this guide was built to close.
Shieldworkz has developed the IEC 62443 Evidence-Backed OT Security Level Assessment - a structured, audit-ready methodology that maps every System Requirement (SR) across all seven Foundational Requirements of IEC 62443-3-3 to specific, verifiable evidence. This is not a checkbox exercise. It is a working tool designed to produce a defensible Security Level rating you can stand behind in front of regulators, boards, and auditors.
Why This Assessment Guide Matters Right Now
The IEC 62443 standard remains the most widely referenced framework for securing Industrial Automation and Control Systems (IACS) globally. But the standard alone does not tell your security team how to collect evidence, score maturity, or communicate gaps to leadership in a language that drives action. That is the problem this guide solves.
Industrial environments are operating in a threat landscape that has fundamentally shifted. Ransomware operators are now deliberately crossing the IT-OT boundary. Nation-state actors are targeting critical infrastructure with tools specifically designed for IACS environments - not generic IT intrusion kits. And the consequences of a successful attack on your OT environment are not a data breach notification. They are process disruption, equipment damage, regulatory enforcement, and in the worst scenarios, safety incidents.
The IEC 62443 framework defines four Security Levels - from SL 1, which addresses accidental or unintentional threats, through to SL 4, which accounts for well-resourced, state-sponsored adversaries with deep industrial control knowledge. Where does your system currently sit? More importantly - can you prove it?
What Makes This Guide Different
There is a principle built into every page of this assessment tool: no score without evidence.
A verbal confirmation from an engineer that a control exists earns a maximum score of 1 out of 4. Anything above that requires a verifiable, time-stamped artifact logged in an evidence register - a configuration export, a policy document, an audit report, a SIEM screenshot. If you cannot produce it to an auditor within 48 hours, the score is zero.
This standard exists because OT security teams often operate on assumptions. They assume the patch is deployed. They assume MFA is enforced on the VPN. They assume the backup is current. This guide replaces assumptions with structured evidence collection across every zone and conduit in your IACS - from field devices and PLCs at Purdue Level 0-1 all the way through the enterprise DMZ.
Key Takeaways From This Assessment Guide
Complete FR-by-FR scoring framework across all seven Foundational Requirements - Identification & Authentication Control, Use Control, System Integrity, Data Confidentiality, Restricted Data Flow, Timely Response to Events, and Resource Availability
Evidence pre-checklists for each Foundational Requirement, so your team knows exactly which artifacts to collect before a single interview or walkthrough begins
Zone and Conduit Pre-Assessment table aligned to IEC 62443-3-2, ensuring your scope covers every logical and physical grouping of assets - not just the systems someone remembered to include
A structured Evidence Register that assigns unique document tags to every artifact, creating a traceable, audit-ready package your legal and compliance teams can actually use
Score-to-Security Level mapping that makes clear what each score means - and why the overall achieved SL is determined by your lowest FR score, not an average (a single weak foundational area brings your entire SL rating down)
Gap Analysis and Remediation Roadmap with a priority framework that categorizes findings as High, Medium, or Low based on safety impact, regulatory exposure, and feasibility - giving your OT security improvement program a defensible starting point
Assessor Declaration and Sign-Off structure, so the completed assessment constitutes a formal, attributable document - not an informal internal review
How Shieldworkz Supports Your OT Security Journey
Shieldworkz works directly with asset owners, industrial operators, and OT security teams across critical infrastructure sectors to move organizations from assessed to secured. Our approach is built around the same evidence-first, standards-aligned methodology embedded in this guide.
We conduct IEC 62443-aligned OT Security Level Assessments, producing audit-ready findings your leadership and regulators can review with confidence
We support compliance readiness across NIS2, NERC CIP, IEC 62443, and applicable regional regulatory requirements
Our team bridges the gap between IT security operations and OT engineering - we speak both languages, and we understand why a generic IT security tool is not sufficient in an IACS environment
We deliver structured remediation roadmaps with prioritized action plans, not just lists of findings
We provide ongoing OT security monitoring, threat detection, and incident response capabilities purpose-built for industrial environments
Take the First Step Toward a Defensible OT Security Posture
Your next regulatory audit, board presentation, or risk committee meeting will ask the question every OT leader is already losing sleep over: Can we demonstrate our security level - and can we prove it?
This guide gives you the methodology to answer that question with evidence, not estimates.
Fill out the form below to download the IEC 62443 Evidence-Backed OT Security Level Assessment - and book your free consultation with a Shieldworkz OT security expert. We will walk through your current environment, help you identify your highest-priority gaps, and show you what a realistic path to your target Security Level looks like.
Download your copy today!
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