ICS/SCADA OT Cybersecurity Self-Assessment: NIST-Based Procedure for Critical Infrastructure

This procedure provides a systematic approach for conducting cybersecurity self-assessments of Industrial Control Systems (ICS) and Supervisory Control and Data Acquisition (SCADA) systems within Operational Technology (OT) environments. Aligned with NIST 800-82 standards, it is designed to assist organizations in evaluating their critical infrastructure security posture and identifying areas for improvement.
The procedure is applicable to critical infrastructure sectors, including:

• Oil and Gas Facilities
• Water and Wastewater Management Systems
• Chemical Plants
• Manufacturing Facilities
• Transportation Networks
• Other OT environments

Industrial Control Systems are increasingly vulnerable to cyber threats that can cause significant operational and physical disruptions. These include:

• Targeted ICS malware (e.g., Stuxnet-like attacks)
• Unauthorized valve or actuator operations
• Alarm system manipulation
• Equipment disablement or sabotage
• Data exfiltration from critical systems
• Ransomware targeting ICS/SCADA networks
• Exploitation of network vulnerabilities
• Physical breaches compromising critical systems

The cybersecurity self-assessment is structured into five key functions based on the NIST Cybersecurity Framework: Identify, Protect, Detect, Respond, and Recover.

Identify

Asset Management

• Maintain up-to-date inventory of OT assets, including hardware, software, and firmware versions.
• Assign management responsibilities for critical network components such as firewalls, routers, and switches.
• Implement regular firmware update procedures to patch known vulnerabilities.
• Define and enforce authentication protocols for all access points.
• Establish a formal patch management program with defined timelines and responsibilities.

Business Environment

• Restrict access to sensitive operational data and enforce role-based access controls.
• Integrate OT security requirements into organizational business planning processes.
• Maintain an active authorization process for OT system changes.
• Establish clear governance structures for OT security programs.
• Create workforce training initiatives to improve cybersecurity expertise unique to OT.

Governance

• Clearly define security responsibilities for all personnel involved in OT systems.
• Implement supply chain risk management policies to address vendor-related vulnerabilities.
• Establish network segmentation policies to isolate critical ICS/SCADA components.
• Maintain accessible and current security documentation for all OT systems.
• Define standardized procedures for integrating new systems into existing networks.

Risk Assessment

• Conduct regular risk assessments focusing on the impact of potential cyber threats.
• Identify and prioritize critical infrastructure sites for enhanced security measures.
• Implement threat modeling techniques to anticipate and mitigate risks.
• Periodically review and update risk assessment policies.
• Establish a consistent schedule for reassessing vulnerabilities.

Supply Chain Risk Management

• Develop policies to evaluate and manage vendor-related risks.
• Implement screening and verification procedures for third-party components and software.
• Maintain a detailed software bill of materials (SBOM) for all OT systems.
• Define secure disposal procedures for obsolete hardware and software components.

Click here for Network Switches requirements in “SCADA” and “DCS” Architecture

Protect

Physical Security

• Control access points to facilities housing ICS/SCADA systems.
• Issue unique identification credentials to all authorized personnel.
• Monitor physical access using surveillance and logging systems.
• Secure devices such as servers, workstations, and control panels against unauthorized access.
• Conduct annual reviews of access authorizations and policies.

Awareness and Training

• Provide targeted cybersecurity awareness training for all OT technicians.
• Conduct regular emergency response drills to simulate cyber incidents.
• Document all training activities and ensure compliance with organizational policies.
• Implement periodic refresher courses to address new threats and best practices.
• Incorporate practical cybersecurity exercises to improve preparedness.

Data Security

• Enforce multi-factor authentication for accessing critical systems.
• Develop and maintain disaster recovery plans for OT systems.
• Ensure secure server configurations during deployment.
• Implement routine backup procedures for critical data and verify restoration processes.
• Protect data while it’s in transit and at rest by using encryption.
• Manage cryptographic keys securely, ensuring regular rotation and access control.

Maintenance

• To avoid unwanted access, keep an eye on and regulate remote maintenance sessions.
• Audit all maintenance activities and maintain detailed logs.
• Develop and document standardized maintenance procedures.
• Securely store and manage maintenance tools and software.
• Maintain an inventory of critical spare parts to ensure system continuity.

Detect 

Anomalies and Events

• Continuously monitor system events for signs of irregular activity.
• Use intrusion detection systems (IDS) to detect and respond to cyberattacks.
• Identify unauthorized access attempts and investigate their origin.
• Strategically place monitoring devices at critical points within the network.
• Set up real-time notifications to inform operators of possible threats.

Security Continuous Monitoring

• Establish protocols for system-wide event monitoring.
• Ensure proper time synchronization across all devices to facilitate accurate logging.
• Evaluate the effectiveness of intrusion monitoring systems regularly.
• Control network access points to prevent unauthorized connections.

Detection Processes

• Authorize and document all methods of remote access to the OT environment.
• Employ cryptographic methods to protect sensitive communication.
• Restrict access points to minimize exposure to threats.
• Manage session termination to prevent unauthorized reconnections.
• Define and enforce policies for integrating external systems.

Respond

Response Planning

• Develop incident handling procedures tailored to OT environments.
• Coordinate contingency planning efforts with all relevant stakeholders.
• Document all security incidents for analysis and reporting purposes.
• Report incidents to appropriate authorities in accordance with legal requirements.
• Ensure adequate support and resources for incident response activities.

Communications

• Information about emergency contacts should be clearly displayed in buildings.
• Maintain secure communication channels for use during incidents.
• Conduct communication drills to ensure readiness during emergencies.
• Regularly update contact lists for critical personnel and external partners.
• Implement and test alarm systems to ensure functionality.

Analysis and Mitigation

• Develop systematic processes for analyzing security incidents.
• Conduct vulnerability assessments to identify weaknesses in the OT environment.
• Account for environmental hazards when designing mitigation measures.
• Plan and implement risk reduction strategies to address identified vulnerabilities.
• Consider accessibility issues when responding to incidents.

Recover

Recovery Planning

• Establish comprehensive recovery management plans for ICS/SCADA systems.
• Review and revise recovery strategies often to account for environmental changes.
• Align recovery plans with the organization’s enterprise architecture.
• Incorporate change management processes into recovery planning.

Communication and Improvement

• Maintain clear and consistent communication about the status of recovery efforts.
• Develop alternate communication channels to address potential disruptions.
• Record and analyze recovery times to identify improvement opportunities.
• Document lessons learned and integrate them into updated recovery procedures.
• Conduct periodic drills to test and refine new recovery methods.

Click here for Protocols and Standards in Industrial Automation: A Guide to OT Cybersecurity

Assessment Documentation

For each assessment area:

• Record the current implementation level for all controls.
• Identify areas where controls are insufficient or missing.
• Outline actions needed to address identified gaps.
• Establish realistic deadlines for remediation efforts.
• Monitor and document implementation progress.

Review and Update

• Conduct an annual review of this procedure to ensure its continued relevance.
• Update the procedure based on new threat intelligence and lessons learned.
• Use insights from previous assessments to refine the process.
• Make sure it conforms with the most recent industry best practices and standards.

Downloadable Checklist for ICS / SCADA OT Cybersecurity Self-Assessment 

This ICS / SCADA OT Cybersecurity Self-Assessment Checklist helps organizations assess their operational technology systems’ security posture, identifying potential vulnerabilities and implementing proactive measures.

Download ICS SCADA OT Cybersecurity Self-Assessment Checklist

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FAQ on  ICS SCADA OT Cybersecurity Self-Assessment

What is a NIST Self-Assessment?

The NIST 800-171 Basic Assessment is a self-evaluation process for organizations to determine their compliance with Controlled Unclassified Information (CUI) security requirements.

What is SCADA in Critical Infrastructure?

A Supervisory Control and Data Acquisition (SCADA) system enables remote monitoring and control of complex processes from a central location, making it essential for critical infrastructure but also vulnerable to cyber threats like ransomware and malware.

What is the NIST Framework for Improving Critical Infrastructure Cybersecurity?

The NIST Cybersecurity Framework Core outlines key cybersecurity activities and outcomes in straightforward language, helping organizations manage and reduce cyber risks. This framework complements existing cybersecurity practices within an organization.

What are the Steps in the NIST Framework for Incident Response?

Preparation, detection and analysis, containment, eradication, and recovery, and post-event analysis are the four main phases of the NIST incident response lifecycle.

What is ICS/OT?

Industrial Control Systems (ICS) and Operational Technology (OT) are integral to critical infrastructure, blending digital and physical capabilities to operate essential systems, from power grids to industrial assembly lines.

What is a Cybersecurity Self-Assessment?

A cybersecurity self-assessment is a practical tool for organizations to evaluate their cybersecurity infrastructure, policies, and practices, identifying areas for improvement and providing tailored resources.

What are the Six Functions of the NIST Cybersecurity Framework?

Six fundamental tasks are included in the NIST Cybersecurity Framework Core: Govern, Identify, Protect, Detect, Respond, and Recover.. These functions streamline the cybersecurity risk management lifecycle.