ISA/IEC 62443 Security Audit
Industrial contracts increasingly require suppliers to demonstrate IEC 62443 compliance. We audit your OT/ICS environment against ISA/IEC 62443-2-1 and 62443-3-3. You get a roadmap to certification and you meet NIS2 requirements.
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What is an ISA/IEC 62443 security audit?
An ISA/IEC 62443 audit is an assessment of how industrial automation systems conform to the industrial standard, covering gap analysis, Security Level assessment and verification of OT security zones. nFlo runs the full path from audit to certification and delivers a roadmap together with documentation templates; the project takes 2–4 weeks and costs from €14,000.
Contact your account manager
Discuss ISA/IEC 62443 Security Audit with your dedicated account manager.
Without IEC 62443 you lose industrial contracts
From gap analysis to IEC 62443 certification
Gap Analysis
Conformity assessment against IEC 62443-2-1 and 62443-3-3
Security Level
SL-T definition and SL-A verification
Roadmap
Action plan leading to certification
What is an ISA/IEC 62443 security audit?
An ISA/IEC 62443 security audit is an assessment of how industrial automation systems conform to the ISA/IEC 62443 standard, covering the analysis of security zones and conduits, Security Levels (SL) and the maturity of the OT cybersecurity programme.
| Attribute | Value |
|---|---|
| Standard | ISA/IEC 62443 |
| Scope | OT/ICS systems, zones and conduits |
| Levels | Security Levels (SL) 1-4 |
| Duration | 2-4 weeks |
| Price | from €14,000 (as of 2026) |
An industrial contract lost for lack of certification
A manufacturer of industrial machinery lost a tender with a German automotive group. The reason? No IEC 62443 certification. A competitor that held the certificate won despite a higher price. Over the following year, further customers declined for the same reason.
Without IEC 62443 compliance:
- You lose contracts in automotive, energy and pharma - they require certification
- You do not meet the NIS2 requirements for the industrial sector
- Insurers raise premiums or refuse cyber coverage
- You have no systematic approach to OT/ICS security
Certified ISA/IEC 62443 auditors - the full path to compliance
We do not leave you with a report. We guide you from gap analysis through the implementation of recommendations to readiness for a certification audit.
What you get:
- Gap analysis against IEC 62443-2-1 (CSMS) and 62443-3-3 (system requirements)
- Security Level assessment: SL-T (target) definition and SL-A (achieved) verification
- Zones & Conduits analysis - assessment of OT network segmentation
- Report with gaps and risk for every requirement of the standard
- Roadmap to certification with priorities and a timeline
- Documentation templates (policies and procedures required by the standard)
- Support in implementing the recommendations
Who is it for?
This service is for you if:
- You build machinery or devices for industry and your customers require IEC 62443
- You are a critical infrastructure operator (energy, water) - NIS2 requires it
- You are an OT systems integrator - you have to demonstrate conformity with the standard
- You want to put cybersecurity in an industrial environment in order
- You are preparing for IEC 62443 certification
Structure of the IEC 62443 standard
IEC 62443-2-1 - Cybersecurity Management System
Requirements for the organisation operating OT/ICS systems:
- Organisation - roles, responsibilities, awareness
- Risk management - identification, assessment, mitigation
- Policies and procedures - secure development, patching, change management
- Incident response - detection, response, recovery
- Business continuity - backup, DR for OT systems
IEC 62443-3-3 - System Security Requirements
Technical requirements for industrial systems:
- FR 1 - Identification & Authentication - access control
- FR 2 - Use Control - authorisation, least privilege
- FR 3 - System Integrity - malware protection, integrity
- FR 4 - Data Confidentiality - encryption in transit and at rest
- FR 5 - Restricted Data Flow - segmentation, zones & conduits
- FR 6 - Timely Response - logging, monitoring, incident response
- FR 7 - Resource Availability - DoS protection, redundancy
Security Levels - SL-T vs SL-A
The standard defines four security levels:
- SL 1 - Protection against accidental violations
- SL 2 - Protection against intentional attacks using simple means
- SL 3 - Protection against sophisticated attacks (skilled attacker)
- SL 4 - Protection against APT attacks (nation-state)
SL-T (Target) - the intended security level (required by the customer or the sector) SL-A (Achieved) - the current security level (verified by the audit)
Most of industry targets SL 2, critical infrastructure SL 3.
Zones & Conduits
A key concept of IEC 62443:
Zone - a group of assets with similar security requirements Example: the SCADA zone, the PLC zone, the HMI zone
Conduit - a secured communication channel between zones Example: an OT firewall between SCADA and PLC
The audit verifies:
- Whether the segmentation matches the risk assessment
- Whether the conduits have adequate controls (firewall, encryption)
- Whether the Security Level is consistent within a zone
Related glossary terms
Learn more about the key concepts related to this service:
Why nFlo?
nFlo is a team of experienced cybersecurity specialists with over 500 delivered projects. Within the ISA/IEC 62443 Security Audit service we offer:
- A team of certified experts — our specialists hold CISSP, CISA, CEH, OSCP and other certifications recognised in the industry
- A methodical approach — we run every project against recognised standards (ISO 27001, NIST CSF, CIS Controls)
- A report with concrete recommendations — we do not only identify problems, we deliver a prioritised list of remediation actions
- Post-project support — we help implement the recommendations and track progress
- 98% client retention — our results speak for themselves
What does the delivery process look like?
- Initial meeting and needs analysis — we get to know the specifics of your organisation, your IT infrastructure and your regulatory requirements
- Scope and schedule — we define the scope of work, the methodology and the timeline
- Delivery — our experts carry out the work according to the agreed plan
- Reporting — we deliver a detailed report with findings, risk assessment and prioritised recommendations
- Presentation of results — we discuss the findings with the technical team and the management board
- Implementation support — we help plan and implement the remediation actions
How we work
Our proven service delivery process.
Kick-off
Scope, objectives, target Security Level
Documentation
Review of policies, procedures and OT documentation
Technical verification
Zones & conduits, configuration, security controls
Gap Report
Report with gaps and Security Level assessment
Roadmap
Prioritised plan leading to certification
Benefits for your business
What you gain by choosing this service.
New contracts
You win tenders that require IEC 62443
NIS2 compliance
You meet the requirements for the industrial sector
Customer trust
Certification proves the maturity of your OT security
Production protection
A systematic approach protects against downtime
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Read more →Frequently Asked Questions
Common questions about ISA/IEC 62443 Security Audit.
How long does an IEC 62443 audit take and what does it cover?
The audit takes 2-4 weeks. It covers a gap analysis against IEC 62443-2-1 (cybersecurity management system) and 62443-3-3 (technical requirements), a Security Level assessment (SL-T vs SL-A), zones & conduits analysis and a roadmap to certification.
Which Security Level (SL) should we target?
Most of industry targets SL 2 (protection against intentional attacks using simple means). Critical infrastructure (energy, water) should target SL 3 (protection against sophisticated attacks). We define SL-T based on risk analysis and sector requirements.
Does an IEC 62443 audit also satisfy NIS2 requirements?
Yes. IEC 62443 is recognised by regulators as the reference standard for the industrial sector in the NIS2 context. Our audit identifies gaps against both the standard and the NIS2 requirements.
After the audit, do you help implement the recommendations and prepare for certification?
Yes. We do not leave you with a report. We deliver templates for the required documentation (policies, procedures), support the implementation of technical recommendations and prepare the organisation for a certification audit by an accredited body.