The CIS Critical Security Controls (CIS Controls) provide a prioritized, actionable set of cybersecurity best practices designed to help organizations defend against the most prevalent cyber threats. Originally developed as the SANS Top 20 Critical Security Controls, the framework has evolved over time, with Version 8 released in May 2021 to reflect modern technology environments and emerging threat vectors.
While the CIS Controls were not specifically developed for Operational Technology (OT) or Industrial Control Systems (ICS), many of their principles can still be highly effective when adapted for these environments. For organizations seeking to improve their security posture in a practical, phased, and scalable manner, the CIS Controls can offer a solid foundation, particularly when integrated with OT-specific frameworks like ISA 62443.
In this post we’ll explore:
- The structure and intent of the CIS Controls
- The potential benefits and limitations of applying them in OT/ICS settings
- Best practices for adapting the controls to the constraints and priorities of industrial environments
Overview of the CIS Controls
The CIS Critical Security Controls are organized into 18 top-level Control Areas, which are further broken down into 153 individual Safeguards. Each Safeguard offers prescriptive guidance on how to implement specific cybersecurity practices to reduce risk.
The 18 Control Areas cover a broad range of cybersecurity domains, including:
- Inventory and Control of Enterprise Assets
- Inventory and Control of Software Assets
- Data Protection
- Secure Configuration of Enterprise Assets and Software
- Account Management
- Access Control Management
- Continuous Vulnerability Management
- Audit Log Management
- Email and Web Browser Protections
- Malware Defenses
- Data Recovery
- Network Infrastructure Management
- Network Monitoring and Defense
- Security Awareness and Skills Training
- Service Provider Management
- Application Software Security
- Incident Response Management
- Penetration Testing
A complete listing of the Controls and their Safeguards is available in the Appendix of this post.
One of the standout strengths of the CIS Controls is that each Control is accompanied by a plain-language explanation of its importance. For example, Control 13: Network Monitoring and Defense emphasizes that even well-designed security controls can fail or require tuning to remain effective. By implementing robust monitoring, organizations can achieve situational awareness, allowing for the rapid detection and response to security incidents when they occur.
Each Safeguard is associated with one of the five NIST CSF Functions:
- Identify
- Protect
- Detect
- Respond
- Recover
These are mapped to what the CIS Controls call Implementation Groups (IG).
The Implementation Groups guide prioritization based on organizational maturity and risk exposure. The IGs are numbered as follows:
- IG1 – For small or less mature organizations with limited resources
- IG2 – For mid-sized organizations with moderate cybersecurity needs
- IG3 – For larger or more mature organizations with complex operational and regulatory environments
These Implementation Groups allow organizations to scale their adoption of controls based on capability, not complexity, making CIS especially appealing for phased OT/ICS security programs. The following table shows the various ways the CIS Control Implementation Groups are described.
Potential Benefits for OT/ICS Environments
Although the CIS Critical Security Controls were originally designed for traditional IT environments, they offer significant value when thoughtfully adapted to OT/ICS. Their structure, prioritization, and prescriptive nature make them a useful framework for organizations seeking actionable security improvements without starting from scratch. Here are five potential benefits of leveraging the CIS Controls in OT/ICS settings:
1. Prioritized Approach
The CIS Controls are intentionally ranked by effectiveness in mitigating real-world cyberattack vectors. This prioritization helps OT and ICS teams focus limited time and resources on the most impactful security measures first, making the controls particularly helpful for organizations building or maturing a program incrementally.
2. Defense-in-Depth
The Controls span a broad range of domains from asset management and access control to monitoring and incident response. This wide coverage supports a layered, defense-in-depth strategy, which is critical in environments where a single point of failure can have physical or safety consequences.
3. Best Practice Guidance
Each Control is supported by detailed implementation steps and success metrics, providing clear direction to security teams. This specificity is valuable in OT/ICS contexts, where generalized guidance often needs translation into real-world application constraints.
4. Risk Reduction
By directly addressing the most common and effective attack vectors (such as phishing, credential theft, and misconfigurations), the CIS Controls offer immediate, measurable risk reduction, even when full compliance with OT-specific standards like ISA/IEC 62443 may be years away.
5. Compliance Support
CIS provides mappings to major frameworks and regulatory requirements, including NERC CIP, ISA/IEC 62443, NIST CSF, and the TSA Pipeline Security Directive. These mappings are freely available (with registration) and make it easier for organizations to build a multi-framework security program without duplicating effort.
Considerations for OT/ICS Environments
While the CIS Critical Security Controls offer significant value, adopting them within OT and ICS environments requires careful evaluation. OT environments introduce unique operational, safety, and architectural constraints that may not align directly with IT-centric guidance. Here are four important considerations to keep in mind:
1. IT-Centric Design
The CIS Controls were originally developed for traditional enterprise IT systems, which means that some Safeguards may need to be adapted or translated to fit the realities of OT/ICS. Concepts such as centralized patching, automated asset discovery, or endpoint detection may not be feasible or appropriate without modification.
2. Legacy Infrastructure Limitations
Many OT environments still rely on legacy systems—including equipment running on unsupported operating systems, or vendor-provided applications that cannot be modified. These systems may not be capable of supporting modern safeguards like secure configuration baselines or routine patching, which limits full compliance.
3. Operational Impact
OT systems often support real-time operations where uptime and safety are paramount. Safeguards like network segmentation, software whitelisting, or aggressive logging must be planned and tested carefully to avoid unintended disruptions to critical processes. Security should enhance, not compromise, operational safety and reliability.
4. Framework Integration and Alignment
Organizations already using OT-specific standards such as ISA 62443 or NERC CIP may face challenges integrating the CIS Controls without creating overlap, redundancy, or conflicts. A successful implementation requires intentional mapping to ensure complementary coverage and avoid duplicative or conflicting control sets.
Next Steps
If you’re considering implementing the CIS Critical Security Controls in an OT/ICS environment, a thoughtful, tailored approach is essential. While the Controls were originally developed for IT, they can be highly effective in industrial settings when properly adapted. Here are five recommended steps to guide a successful adoption:
1. Conduct a Gap Analysis
Begin by assessing your current cybersecurity posture against the CIS Controls. Identify which Safeguards are already in place, where gaps exist, and prioritize improvements based on risk, resource availability, and operational criticality.
2. Tailor the Controls to Fit Your Environment
Not all CIS Safeguards will be directly applicable to OT systems. Review each Control and Safeguard, then adjust implementation strategies to align with the technical constraints, uptime requirements, and lifecycle limitations of your ICS environment.
3. Develop an Implementation Plan
Create a phased plan for implementing the prioritized Safeguards. Consider operational dependencies, required staffing or tooling, and integration with existing security frameworks.
4. Involve Key Stakeholders Early
Engage your OT operations teams, vendors, and integrators from the start. Their insight is critical for feasibility assessments, operational alignment, and gaining the buy-in necessary for smooth implementation.
5. Seek Expert Guidance
Work with cybersecurity professionals who understand both CIS Controls and industrial systems. This ensures your implementation is technically sound, risk-informed, and aligned with both business and operational priorities.
By carefully evaluating the CIS Controls and adopting a tailored approach, OT/ICS organizations can leverage this valuable framework to strengthen their cybersecurity posture and mitigate common cyber threats.
Enaxy Can Help
At Enaxy, we’ve supported clients across industries in adapting and applying the CIS Controls to complex OT/ICS environments. From gap assessments and roadmap development to stakeholder training and framework integration, we help ensure your security program delivers measurable results without disrupting operations.
Interested in getting started? Reach out to our team at info@enaxy.com.
Appendix
The following table shows the CIS Controls, each of the Safeguards, and their associated Implementation Group. Safeguards shown in purple mean that the Safeguard is a part of that Implementation Group.
