Industrial Control Systems (ICS) face a host of complex challenges and vulnerabilities in today's increasingly connected world.  Understanding how to protect these systems is crucial for cybersecurity professionals and IT managers who are charged with safeguarding critical infrastructure.  

Part of this protective effort are offensive assessments designed to identify vulnerabilities and convey impact, which come in two primary types—Vulnerability Assessments and Penetration Tests. In this blog post, we will explore the differences between these two methodologies and their applications in ICS environments. 

Introduction to Operational Technology (OT) Security 

Understanding OT vs. IT  

Operational Technology (OT) and Information Technology (IT) serve distinct roles within an organization, yet they are increasingly intertwining in the digital age. OT refers to systems and hardware used to monitor and control physical devices, processes, and infrastructure, predominantly found in industrial environments such as manufacturing plants, power grids, and transportation networks. Its primary focus is on ensuring the reliability, safety, and efficiency of operations.  

In contrast, IT is associated with data-centric computer systems, networks, and technologies used to process, store, and secure information, catering mainly to business and administrative functions.  

While both aim to optimize productivity and ensure security, OT prioritizes real-time operational continuity and control, whereas IT emphasizes data integrity and cybersecurity. The convergence of these technologies brings unique challenges and opportunities, necessitating a comprehensive understanding of their nuances and interplay to secure and manage hybrid networks effectively.  

The Need for Offensive Assessments in OT Environments 

Traditional security measures, such as firewalls and antivirus software, are not sufficient to protect OT systems from targeted attacks that exploit inherent vulnerabilities. As technology advances and connectivity increases, the attack surface expands, leaving critical infrastructure exposed to cyber threats. Furthermore, OT environments typically prioritize availability over confidentiality and integrity, making them more susceptible to attacks seeking to disrupt operations or cause physical harm. Consequently, there is a growing need for organizations to conduct offensive assessments that simulate real-world scenarios and test the robustness of their defenses against potential cyber-attacks. 

Offensive Assessments in ICS Environments 

Offensive assessments in OT environments are critical to a robust cybersecurity strategy. Various methods include red teaming, penetration testing, and vulnerability assessments.

Key Assessment Types: 

• Red Team Assessments: Focuses on evasion and threat emulation.  

• Penetration Tests: Collaborates with internal teams to simulate real-world attacks and achieve specific objectives. 

• Device Penetration Tests: Evalutes the attack surface of a specific piece of hardware or vendor application software within an ICS network. 

• Vulnerability Assessments: Identifies vulnerabilities using automated tools without active exploitation. 

Insights from The SANS State of OT/ICS Cybersecurity Survey: 

A significant 75% of organizations conduct annual OT security assessments, underscoring their growing importance in cybersecurity strategies. However, 51% of organizations conducted paper-based vulnerability assessments over the last 3 years compared to the 40% that participated in active vulnerability assessments, and 25% that participated in penetration tests.

While these mark a mainstream practice in cybersecurity, there is a call to action for active vulnerability assessments and penetration tests in industrial environments as these seek to truly validate discovered vulnerabilities and demonstrate impact. In recent years, these engagements show increasing adoption - though the precedent should be set to only conduct them where safe in OT networks. 

Source 

Understanding Vulnerability Assessments 

A vulnerability assessment is a systematic review of security weaknesses in a network and its systems. In the context of ICS, this involves identifying, quantifying, and prioritizing vulnerabilities within the control systems and associated assets. 

Key Characteristics: 

• Broad Scope: Vulnerability assessments cover various components within an environment, including the review of domain, host, and network configurations. 

• Automated Tools: These assessments often leverage automated tools to scan systems for known vulnerabilities. 

• Identification and Prioritization: The main goal is to identify and prioritize vulnerabilities based on their potential impact. 

• Ongoing Process: Regular assessments are pivotal for maintaining security as systems and threats evolve over time. 

  
  

Vulnerability assessments provide a fundamental understanding of the existing weaknesses within a system. However, they do not simulate real-world attack scenarios, which leads us to the next type of assessment. 

The Role of Penetration Testing 

Penetration tests, or pentests, go a step further by simulating cyberattacks to identify and exploit vulnerabilities in a system. They are a proactive measure to validate the effectiveness of security controls and practices within an ICS environment. 

Key Characteristics: 

• Focused Attack Simulation: Penetration tests identify and execute on actual attack vectors to assess the resilience of ICS security measures. 

• Manual and Automated Methods: These tests involve a combination of manual techniques and automated tools to identify vulnerabilities and chain together tactics to advance the attack path. 

• Exploitation: A pentest doesn't just identify vulnerabilities; it attempts to exploit them to demonstrate the potential impact of a real-world attack. 

• Comprehensive Reporting and Remediation Guidance: After a pentest, comprehensive reports are provided, detailing the vulnerabilities found and offering remediation strategies. 

Vulnerability Assessment vs. Pen Test in ICS 

Understanding the distinctions between vulnerability assessments and penetration tests is crucial when it comes to protecting ICS environments. 

When to Use Each: 

• Vulnerability Assessments are ideal for regular checks and maintaining an ongoing awareness of potential security issues. They are less intrusive and can be scheduled more frequently to ensure that new vulnerabilities do not go unnoticed. 

• Penetration Tests should be conducted periodically or when significant changes are made to the systems, such as after major updates or integrations. They offer deeper insights into the security posture by simulating adversarial tactics and techniques. 

Challenges and Considerations: 

• System Sensitivity: ICS environments are often sensitive, and caution must be exercised during assessments to avoid disruptions. It's critical to plan assessments carefully, considering the impact on production systems. 

• Expertise Required: Both vulnerability assessments and pentests require dedicated expertise. For pentests especially, skilled professionals who understand both cybersecurity and the intricacies of ICS are necessary. 

Preparing for Offensive Assessments 

Proper preparation is crucial for successful assessments. Consider these essential elements: 

Set Clear and Focused Goals:   Establishing precise goals and objectives for the engagement ensures it remains targeted and addresses critical issues effectively. Overly broad scopes can lead to missed details and reduced productivity. Organizations should clearly articulate their needs and expectations to enable the assessment team to deliver tailored and impactful results. 

• Comprehensive Documentation: Provide network diagrams, firewall rules, and asset inventories.

• Access and Permissions: Ensure testers have appropriate access to conduct assessments. 

• Clear Rules of Engagement: Define boundaries to ensure safe and effective testing. 

• Involvement of Subject Matter Experts (SMEs): SMEs provide critical insights during assessments. 
  
  

Comparison of Vulnerability Assessments and Pen Tests 

Challenges in OT Environments 

• Safety Concerns: Legacy systems in OT environments are sensitive to active testing. 

• Complexity: Industrial systems require tailored approaches, especially when dealing with fragile or critical devices. 

• Regulatory Requirements: Standards like NERC CIP dictate stringent assessment protocols.  

Conclusion 

In the mission to secure Industrial Control Systems, both vulnerability assessments and penetration tests play vital roles. By leveraging these assessments strategically, organizations can enhance their security posture, protect critical infrastructure, and stay ahead of potential threats. 

Cybersecurity professionals and IT managers must weigh the benefits and limitations of each approach, ensuring that both vulnerability assessments and penetration tests are integrated into their overall security strategy. These proactive measures not only safeguard the enterprise but also contribute to the resilience and reliability of our critical infrastructure systems. 

For more insights on ICS security strategies and best practices, stay tuned to our blog or connect with us on our professional network.