A Global Integrated O&G operator sought to modernize its approach to OT cyber risk assessment by adopting a structured, repeatable methodology capable of quantifying cyber‑physical risk across complex operational environments. The organization engaged Armexa to design and deliver a customized OT cyber risk assessment framework, based on industry standards such as ISA/IEC 62443-3-2, to evaluate effectiveness of existing safeguards, strengthen risk communication, and align cybersecurity practices with enterprise risk tolerance criteria.
Problem
The client required a cyber risk assessment method that could bridge the gap between traditional process safety practices and emerging OT/ICS cybersecurity challenges. Existing assessment processes lacked consistency, did not fully account for cyber‑initiated threat scenarios, and offered limited ability to quantify likelihood in a transparent, defensible way.
Key obstacles included:
- Inconsistent documentation of threats, safeguards, and consequences across sites.
- Difficulty aligning cyber scenarios with corporate risk matrices designed for physical‑process hazards.
- Limited integration between cybersecurity analysis and existing PHA work processes.
- Need for a scalable approach that could support global facilities and diverse industrial systems.
Solution
Armexa developed and delivered a tailored CyberBowtie methodology, toolkit, and operational workflow purpose‑built for OT cyber‑physical risk assessment. The solution included:
- Custom PHA‑Pro CyberBowtie Template & Library
A governed template and safeguard library designed to standardize threat modeling, consequence analysis, and safeguard evaluation across OT environments. - Quantitative Likelihood Model Using FAIR‑Based Principles
Integration of structured likelihood factors—threat frequency, source, exploitability, and difficulty—with annualized event rate calculations aligned to the client’s corporate risk matrix. - Three‑Day Facilitated Workshop
Armexa SMEs conducted onsite working sessions to guide assessors through scenario development, template use, safeguard effectiveness evaluation, and Bowtie diagram completion. - Automated Linkage to Corporate Risk Tolerance Framework
Built‑in logic to translate likelihood and consequence severity into consistent residual‑risk ratings using the client’s approved Cybersecurity Risk Tolerance Matrix. - Knowledge Transfer & Documentation
Delivery of a comprehensive operations manual, reference materials, and hands‑on training to equip internal cyber assessors for ongoing, scalable use of the methodology.
Outcome / Benefits / Impact
The engagement resulted in a fully operational OT cyber risk assessment methodology adopted across the client’s organization. Key benefits included:
- Repeatable, Defensible Assessments
A standardized approach that ensures consistent interpretation of cyber threats, safeguards, and risk outcomes across teams and sites. - Improved Alignment Between Cybersecurity and Process Safety
Integration of cyber‑initiated events into established PHA processes strengthened communication between OT, IT, and risk stakeholders. - Enhanced Risk Visibility
Built‑in reporting and visualization tools enabled clearer understanding of residual risk and prioritization of mitigation efforts. - Scalability Across the Enterprise
The customized template, governed safeguard library, and structured methodology support roll‑out across additional operational units and future assessments. - Accelerated Assessor Capability
Through training and documentation, internal teams gained the ability to independently manage assessments and maintain the methodology.
