Prism Infosec is dedicated to strengthening the cybersecurity posture of industrial control systems (ICS) that underpin critical infrastructure. We partner with asset owners and operators to deliver in-depth, assessments based on industry standards, guidelines, and best practices. Our structured methodology empowers organizations to evaluate and validate the resilience of their ICS networks and implement robust defence-in-depth strategies.
During testing, our experts perform a high-level preliminary assessment using the Prism ICS Evaluation Framework, followed by a detailed analysis of network segmentation, system configurations, and interconnectivity to both internal and external networks. This step provides a comprehensive view of the control system’s defensive posture.
The network traffic analysis leverages a combination of open source and commercial tools to examine communications flows, identify anomalous behaviours, and map device relationships within the control system environment. By analysing customer-provided packet captures, we deliver actionable insights into suspicious or unauthorized traffic patterns.
In the system log review, Prism Infosec examines logs from critical ICS components such as HMIs, historians, and control servers to detect indicators of compromise or configuration weaknesses. Our consultation culminates in the detailed report of findings and prioritized recommendations, charting a clear path toward enhanced security and operational resilience.
The Security Architecture Review (SAR) is an essential, strategic first step in evaluating ICS/OT environments, particularly when dealing with Critical National Infrastructure. Due to the sensitive nature of these systems and the potential risks of significant consequences if compromised, we propose conducting a SAR before any in-depth active technical assessments or security testing activities take place. This ensures ample focus on analysis, communication, and actionable outcomes.
At its core, the SAR functions as a non-intrusive, risk-driven assessment a “pen-and-paper pen test” designed to map out systemic weaknesses and architectural exposures without physically interacting with live systems. The process is structured around engaging engineers within the organization through targeted interviews to gain a deep understanding of operational priorities, security practices, and risk appetite. Our consultants then examine any available network diagrams and asset inventories to evaluate segmentation, visibility, and asset coverage across the environment. A configuration review is also carried out to assess access controls, protocol use, and defensive tooling.
Unlike regulatory audits, the SAR is not framework-bound. It does not align itself with a specific compliance model such as IEC 62443, nor is it driven by a checklist methodology. Rather, it provides a comprehensive and holistic understanding of how well the environment is architected to withstand cyber threats and operational disruptions.
One of the main advantages of a SAR is speed. It delivers valuable security insight and strategic recommendations in a matter of days, rather than weeks. It helps to pinpoint high-likelihood, high-impact risks early and provides organizations particularly those new to ICS assessments with a pragmatic starting point. The outputs of the SAR also help establish task priorities and build a roadmap for remediation, tailored to the specific business and operational realities of the client’s environment.
By conducting this review at the outset, we reduce the uncertainty and potential disruption associated with more invasive testing. We are also able to ensure that any subsequent assessments are both targeted and meaningful. The SAR creates clarity for stakeholders, improves delivery accuracy, and sharpens the overall security posture well before entering the riskier phases of the engagement.
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