Understanding OT Penetration Testing
A penetration test (pen test) simulates a real-world cyberattack to uncover vulnerabilities, validate security assumptions, and assess an organization’s overall security posture.
These tests are particularly useful for mature organizations that have a clear understanding of their operational environment. By identifying how easily an attacker could exploit weaknesses and measuring the visibility of such activities, businesses can strengthen their defenses effectively.
Key Types of Penetration Tests
Penetration testing involves security professionals manually evaluating an environment using adversary-like techniques. There are three primary types of penetration tests:
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White-Box Pen Test – The organization shares extensive information about its infrastructure with the assessment team, enabling an in-depth security review.
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Grey-Box Pen Test – A moderate level of information is shared, striking a balance between real-world conditions and controlled testing.
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Black-Box Pen Test – Little to no prior knowledge is provided, closely mimicking an external attack scenario.
For industrial environments, grey-box and white-box tests are recommended due to the sensitivity of industrial control systems. Testing without prior knowledge (black-box) can be hazardous, as even simple actions like port scanning could disrupt critical processes.
Clear rules of engagement and risk assessments are essential before proceeding.
Defining the Scope of an OT Pen Test
A penetration test’s scope should align with the organization’s security objectives. Common scopes include:
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External Pen Test – Assesses external threats by targeting publicly accessible network services such as remote access or file transfer tools. Ideal for remote industrial sites.
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IT/OT Border Pen Test – Evaluates the security of the boundary between corporate IT and industrial OT networks. This is the most common OT pen test.
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Industrial Control Systems (ICS) Pen Test – Examines software and systems that manage industrial processes. Conducted only on nonproduction environments to prevent operational disruptions.
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Device Pen Test – Tests the security of specific hardware such as Programmable Logic Controllers (PLCs) or Remote Terminal Units (RTUs) in a controlled lab environment.
Maximizing the Value of an OT Vulnerability Assessment
To ensure an effective penetration test, organizations should follow these best practices:
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Engage operations and engineering teams early for support and cooperation.
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Clearly define objectives, expected outcomes, and test scope.
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Establish comprehensive rules of engagement and safety protocols.
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Assess potential risks and impacts before conducting any tests.
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Ensure test systems are available and isolated from live production environments.
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Set up clear communication channels for real-time approvals and responses.
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Ensure cross-functional teams, including OT, IT, security, engineering, and leadership, are involved throughout the process.
Deliverables: What to Expect from an OT Pen Test
The results of an OT penetration test come in two parts:
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Engagement Activities – Real-time interactions and simulated adversary activities help organizations assess their detection and response capabilities.
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Comprehensive Report – This document details all exploited vulnerabilities, maps each tactic, technique, and procedure (TTP) to the MITRE ATT&CK ICS framework, and provides actionable recommendations. The focus is on strengthening preventive and detective security controls to mitigate identified attack paths.
By conducting a well-scoped and thoroughly planned OT penetration test, organizations can proactively enhance their cybersecurity resilience, ensuring their industrial environments remain protected against evolving threats.
Learn more about Insane Cyber’s OT Pen Tests and more.