As the threat landscape targeting critical infrastructure continues to evolve, the North American Electric Reliability Corporation (NERC) has introduced CIP-015-1 to address a critical gap in cybersecurity: visibility within internal networks. While previous CIP standards have focused heavily on perimeter defenses, CIP-015 shifts attention inward, toward detecting malicious activity that has already bypassed traditional defenses.
For organizations operating Industrial Control Systems (ICS) and Operational Technology (OT), CIP-015-1 presents both a challenge and an opportunity. Implementing CIP-015 effectively requires balancing enhanced security monitoring with the foundational priorities of Safety, Reliability, and Performance (SRP). This blog explores what CIP-015 entails, why it matters, and how organizations can approach compliance without compromising operational integrity. While the CIP-015 requirements only apply to electric utilities, as one of the oldest mandatory cybersecurity standards in effect the CIP standards have served as a model for other OT/ICS-focused standards and industries over the years.
What is NERC CIP-015?
NERC CIP-015, titled “Cyber Security — Internal Network Security Monitoring (INSM)”, is designed to improve detection capabilities within trusted network zones. It focuses on identifying anomalous or potentially malicious activity inside Electronic Security Perimeters (ESPs), where traditional perimeter defenses offer limited protection.
Key Requirements and Practical Implications
CIP-015 is not just a technical control; it is an operational shift. Organizations must rethink their approach to network visibility in environments where downtime and disruption are unacceptable.
At its core, CIP-015 requires organizations to:
- Establish baselines of normal network behavior
- Monitor for deviations from those baselines
- Generate alerts for suspicious activity
- Investigate and respond to identified anomalies
This represents a significant enhancement to detection and response capabilities in NERC CIP environments.
In-Scope Systems
The NERC CIP standards generally apply to the electric industry and those organizations which own and operate the Bulk Electric System (BES). If you’re new to electric sector cybersecurity you can read An Introduction to the NERC CIP Standards for a background on the NERC CIP regulations and what systems the standards apply to. For CIP-015-1, the in-scope systems only include high impact BES Cyber Systems (BCS), which are at electric utility Control Centers, and medium impact BCS with External Routable Connectivity, or communication links beyond their local network.1
Establishing Baselines
Before detecting anomalies, organizations must understand what “normal” looks like. This includes:
- Typical communication patterns between devices
- Expected protocols and ports
- Normal timing and frequency of operations
In OT environments, this is both easier and harder than in IT. It is easier because systems are often deterministic, but harder because legacy systems may lack documentation. A practical approach uses passive network monitoring tools that learn patterns without affecting operations, typically by monitoring a network TAP or SPAN feed.
Monitor for Deviations
CIP-015 requires ongoing monitoring, not periodic audits. This is different from most “traditional” NERC CIP requirements and introduces challenges around how to handle the large volumes of network data that may be in scope, avoid “alert fatigue” from too many false positives, and integrate the monitoring into existing workflows.
Solutions must be designed with low overhead and high fidelity, ensuring they do not interfere with real-time control processes.
Anomaly Detection and Alerting
Not all anomalies are threats. The key is distinguishing between:
- Operational changes (e.g., maintenance activities)
- Misconfigurations
- Genuine cyber threats
Organizations should implement contextual alerting that incorporates asset criticality and operational state.
Incident Response Integration
Detection without response is ineffective. CIP-015 implicitly ties into incident response processes by requiring:
- Investigation of alerts
- Documentation of findings
- Timely remediation actions
This requires coordination between cybersecurity teams and operations personnel, groups that have historically operated in silos.
Implementation Dates
The CIP-015 requirements include a phased implementation approach. The regulatory order implementing the standards was published in September 2025 and included a three-year window before entities had to ensure compliance with the standard, leading to an effective date of October 1, 2028. However, this date only applies to high impact Control Centers, since they pose a higher risk to the reliability of the Bulk Electric System. After an additional 24 months (October 1, 2030) the enforcement will expand to include medium impact BCS with External Routable Connectivity.
One of the reasons the delayed effective date was included with CIP-015-1 is because there are a limited number of vendors and personnel experienced in large-scale deployment of ICS-focused Network Security Monitoring systems, and using the phased approach allows for focusing on more critical sites first.
Challenges in ICS/OT Environments
Organizations may run into some common problems with implementing an INSM program.
Availability Constraints
Unlike IT systems, OT environments cannot tolerate downtime. Any monitoring solution must be:
- Passive
- Non-intrusive
- Proven not to impact system performance
Skills Gap
Effective implementation requires expertise at the intersection of cybersecurity and industrial operations. You are unlikely to be able to just “turn on the monitoring” like you might in a corporate, cloud-based environment.2 Everything from deploying INSM sensors into remote networks to tuning the tools in order to actually gain value from them can represent a steep learning curve if you haven’t done it before.
Best Practices for CIP-015 Implementation
Organizations that succeed with CIP-015 will take a strategic, risk-based approach rather than treating it as a compliance checkbox.
Leverage Passive Monitoring Technologies
Deploy tools that:
- Analyze network traffic without injecting packets
- Understand industrial protocols
- Provide behavioral analytics
While it may be possible to “roll your own” tool to address INSM requirements, this capability represents the most mature sector, vendors, and tools in ICS cybersecurity. Utilize that expertise and experience to ensure your rollout goes smoothly.
Align with SRP Priorities
Every security control should be evaluated through the lens of:
- Safety: Does it introduce risk to personnel or processes?
- Reliability: Could it disrupt operations?
- Performance: Does it degrade system efficiency?
CIP-015 implementations that ignore SRP will face resistance from operations teams.
Focus on Use Cases, Not Just Compliance
Rather than asking “Are we compliant?”, ask:
- Can we detect lateral movement?
- Can we identify unauthorized device communication?
- Can we respond before operations are impacted?
This mindset leads to stronger security outcomes.
Emerging Trends and Future Outlook
CIP-015 reflects a broader industry shift toward zero trust principles in OT environments. While full zero trust may not yet be practical for many ICS systems, elements such as continuous monitoring and behavioral analysis are becoming essential. As threats become more sophisticated, internal visibility will no longer be optional, it will be foundational. By focusing on internal network visibility, it addresses one of the most significant blind spots in the NERC CIP requirements.
For ICS and OT environments, the challenge lies in implementing these capabilities without compromising Safety, Reliability, and Performance. Organizations that take a thoughtful, risk-based approach will not only achieve compliance but also significantly strengthen their security posture.
If your organization is navigating the complexities of NERC CIP-015 or looking to enhance visibility within your OT environment, expert guidance can make all the difference. Reach out to info@enaxy.com to discuss your challenges and explore practical, SRP-aligned solutions tailored to your needs.
1 This is simplified, but it will suffice for the purposes of this post.
2 There is, of course, often an impact to the pocketbook to turn on the monitoring in cloud environments.