OT Security Resident Engineer

OT Security Resident Engineer

Core Responsibilities

Design and Strategic Planning

• Define and evolve the enterprise OT security architecture, reference models, security zones, conduits, and trust boundaries (e.g., Purdue Model / ISA-95) for new and existing plants and sites.

• Set architecture standards for firewalls, segmentation, remote access, and secure protocols; lead architecture reviews and risk assessments for OT projects.

• Own and evolve the OT security roadmap and target-state architecture.

Technical Security Implementation

• Translate architecture into low-level designs (LLDs) and implementation guides; engineer firewalls, IDS/IPS, NAC, endpoint protection, secure remote access, and OT monitoring tools (e.g., Claroty, Nozomi, Dragos).

• Define secure configuration/hardening baselines for PLCs, RTUs, HMIs, engineering workstations, and historians; design logging, SIEM integration, and asset visibility solutions.

• Lead vulnerability assessments and patch management strategy; design backup, recovery, and restoration architecture, including secure air-gapped backups and removable media/USB controls.

Network Infrastructure Planning

• Design segmented, resilient OT networks (Purdue Levels 0-5), including VLAN structures, routing, and redundancy/failover mechanisms.

• Architect secure IT/OT interconnection (industrial DMZ, data diodes, one-way gateways) and secure wireless, remote, and third-party/vendor connectivity.

• Validate designs through diagrams, data flow mapping, and threat modelling; define time synchronization, redundancy protocols (PRP/HSR, RSTP), and real-time traffic requirements.

Governance and Regulatory Alignment

• Lead OT cybersecurity risk assessments, identify gaps, and define remediation strategies.

• Ensure architecture and deployments align with regulatory, industry, and corporate compliance requirements; support audits and certifications.

• Define security levels (SL-T) and zone/conduit requirements per IEC 62443, and track control gaps to closure.

System Integration and Interoperability

• Define integration architecture across firewalls, switches, SIEM/SOC, NMS, PAM, and other cybersecurity infrastructure.

• Ensure interoperability and data flow standards between OT security tools and enterprise/IT security platforms.

• Conduct post-incident architecture reviews, feeding lessons learned into architecture standards and control design.

Documentation

• Own and maintain architecture blueprints, design standards, reference diagrams, and configuration baselines.

• Establish templates for HLD/LLD, network diagrams, port matrices, and as-built documentation.

Stakeholder & Vendor Management

• Act as senior technical authority for OT cybersecurity architecture across OT operations, IT, SOC, engineering, and OEM/vendor teams.

• Lead architecture and design review boards; present and defend design decisions to stakeholders and leadership.

• Manage OEM/vendor relationships and embed security requirements into RFPs, contracts, and integrator scopes of work.

Knowledge Transfer

• Provide technical mentorship to site teams on architecture and design best practices.

• Develop training material and lead knowledge-transfer sessions to build OT security capability.

• Foster a security-aware culture across OT operations and engineering staff through awareness and training.

Skills & Experience

• 6+ years in cybersecurity, with strong OT/ICS security architecture and industrial network security experience

• Skilled in network security: firewalls, routing/switching, VLANs, segmentation, IDS/IPS, VPN, secure remote access

• Experience with SIEM/SOC solutions, including logging, monitoring, alerting, and OT use cases

• Experience with OT security monitoring/asset visibility tools (Nozomi Networks preferred; Claroty, Dragos also acceptable)

Certifications (Preferred)

• GICSP, IEC 62443, or CISSP

• CCNA/CCNP Security or equivalent

• Nozomi Networks (NNCE) or equivalent OT platform training

• Fortinet, Cisco, or equivalent firewall/network security certification

• Splunk, Microsoft Sentinel (SC-200), QRadar, or equivalent SIEM certification

… more