ICS Security Assessment
Security assessment of Industrial Control Systems using IEC 62443 and NIST frameworks.
ICS Security Assessment
Industrial Control Systems underpin the operation of power grids, water treatment plants, oil and gas pipelines, and manufacturing facilities — making their security a matter of national importance. Intelliroot's CREST-certified ICS specialists conduct comprehensive security assessments aligned to IEC 62443 and NIST SP 800-82, covering the full Purdue model from Level 0 field devices through to the enterprise DMZ. Every assessment is conducted with a passive-first methodology to ensure absolutely zero disruption to live industrial processes.
Our assessors bring hands-on experience across diverse OT environments including DCS, PLC, RTU, and historian platforms from major vendors such as Siemens, Rockwell Automation, ABB, Honeywell, and Emerson. We move beyond checklist audits to provide a true adversarial perspective on how an attacker could traverse from the IT network into the OT environment — and what that means for operational safety and business continuity.
Why ICS Security Cannot Be Deferred
OT Is Under Active Attack
Nation-state actors and ransomware groups are actively targeting ICS environments. Incidents at Colonial Pipeline, TRITON/TRISIS, and Industroyer demonstrate that OT attacks can halt operations and endanger lives.
IT/OT Convergence Opens New Paths
Digital transformation and remote access requirements have bridged traditionally air-gapped OT networks to corporate IT — creating lateral movement paths that attackers exploit before operators are aware of the exposure.
Regulatory Mandates Are Tightening
NCIIPC CII sector guidelines, CERT-In Directions 2022, NIS2 in Europe, and NERC CIP in North America all require periodic security assessments of operational technology environments.
Legacy Systems Cannot Be Patched Like IT
OT asset lifecycles span decades. Unpatched PLCs, legacy SCADA software, and unsupported operating systems require compensating controls and network-layer mitigations that only a specialist OT assessment can correctly prescribe.
What the Assessment Covers
Asset Inventory & Architecture Review
- Passive OT asset discovery and inventory validation
- Purdue model zone and conduit mapping
- IT/OT interface and DMZ architecture review
- Remote access path enumeration (VPN, jump servers, vendor access)
- Undocumented or rogue device identification
Network Segmentation & Protocol Security
- Firewall rule review for OT-facing interfaces
- VLAN and zone boundary validation
- Industrial protocol security (Modbus, DNP3, Profibus, EtherNet/IP)
- Unencrypted protocol exposure analysis
- Broadcast domain assessment for OT segments
Engineering Workstation & Historian Security
- Engineering workstation hardening review
- Historian server security configuration
- Removable media and USB policy assessment
- Patch management feasibility and compensating controls
- Anti-malware and application whitelisting review
Access Control & Patch Management
- Privileged access management for OT systems
- Default and shared credential review
- Vendor remote access governance
- OT patch management programme assessment
- Safety system separation and interlock review
Our Assessment Approach
Scoping & OT Environment Briefing
Engage plant managers, ICS engineers, and IT/OT teams to understand the operational environment, define assessment boundaries, agree on passive-first rules of engagement, and identify safety-critical systems that require additional protection protocols.
Passive Asset Discovery & Architecture Mapping
Deploy passive network monitoring (aligned to Dragos and Claroty methodologies) to build a comprehensive asset inventory without generating traffic that could disrupt controllers or trigger safety interlocks. Map all Purdue model zones, conduits, and IT/OT interfaces.
Configuration Review & Document Analysis
Review firewall configurations, network diagrams, access control lists, patch records, vendor access logs, and change management documentation against IEC 62443 and NIST SP 800-82 control requirements.
Targeted Vulnerability Analysis
Perform controlled, low-impact vulnerability analysis against identified OT assets — prioritising known ICS CVEs, default credentials, unencrypted communications, and unsafe remote access configurations using purpose-built OT security tooling.
Risk Characterisation & Reporting
Characterise each finding in OT risk terms — operational impact, safety implications, likelihood of exploitation, and regulatory relevance. Deliver a detailed technical report and executive summary with a prioritised remediation roadmap tailored to OT maintenance windows.
Frequently Asked Questions
Deliverables
ICS Security Assessment Report
Comprehensive technical findings covering all Purdue model zones, vulnerabilities identified, and risk characterisation in OT operational terms.
OT Asset Inventory
Validated inventory of all discovered OT assets with vendor, model, firmware version, communication protocols, and zone classification.
Network Architecture Diagram
Annotated network topology showing Purdue model zones, conduits, IT/OT interfaces, and identified exposure points.
IEC 62443 / NIST 800-82 Gap Register
Control-by-control gap assessment mapped to IEC 62443 and NIST SP 800-82 with maturity scoring and remediation priorities.
OT Remediation Roadmap
Phased remediation plan structured around OT maintenance windows, operational constraints, and asset lifecycle considerations.
Request a Security Assessment
Tell us about your environment and security objectives. We'll design a bespoke assessment and deliver a detailed proposal within 48 hours.