A leading refinery in the energy sector recognized the urgent need to strengthen the security of its Operational Technology (OT) and Industrial Control Systems (ICS). With the rising sophistication of cyber threats and compliance requirements from ISA/IEC 62443 and the NIST Cybersecurity Framework 2.0, the refinery engaged Arista Cyber to conduct a comprehensive OT Cyber Risk Assessment.

The Challenge

• Limited visibility into OT /assets and vulnerabilities.
• Outdated policies and procedures not aligned with evolving standards.
• Legacy network architecture lacking segmentation and defense-in-depth.
• Gaps in security controls, patching, and configuration management.
• Insufficient staff awareness of OT cyber threats.
• No clear compliance roadmap, creating uncertainty for audit readiness.

Our Approach

• Risk Identification & Evaluation of OT /assets, processes, and systems.
• Policy & Procedure Review of governance and incident readiness.
• Network Security Architecture Evaluation of OT/ICS design and segmentation.
• Security Control Validation against IEC 62443 and NIST CSF 2.0 best practices.
• Tailored Mitigation Strategy with prioritized, actionable recommendations.

Key Deliverables

• Detailed Assessment Report with prioritized findings.
• Compliance Roadmap & Mitigation Plan aligned with IEC 62443 and NIST CSF 2.0.
• Complete OT/ICS Asset Inventory.
• Purdue-based High-Level Architecture Diagram for segmentation.
• Cybersecurity Dashboard for executive visibility.
• Updated Cybersecurity Policies tailored to refinery operations.
• Awareness Training for engineers, operators, and contractors.
• Host & Configuration Reports for firewalls, switches, and key /assets.

Results & Impact

• Enhanced Cyber Resilience with greater visibility and reduced risks.
• Compliance Confidence with clear roadmap to meet standards.
• Operational Assurance providing leadership with stronger security posture.
• Cultural Transformation by building cybersecurity awareness across staff.