compensating controls

Compensating controls are alternative safeguards put in place when a primary or prescribed control cannot be implemented as written, typically due to technical, operational, or economic constraints. In regulated and industrial environments, they are expected to provide protection that is demonstrably equivalent or comparable to the original control requirement.

Compensating controls can be physical, technical, or administrative. They are selected and justified through a structured risk assessment that documents why the primary control is not feasible and how the compensating measure reduces the relevant risk to an acceptable level.

Characteristics in industrial and regulated environments

• Alternative to a specific requirement: They address the same risk or control objective as the original requirement but use a different mechanism.
• Risk-based justification: Their use is typically based on documented risk assessments, including threat, vulnerability, likelihood, and impact.
• Evidence and traceability: Organizations commonly maintain records showing the mapping from the original control to the compensating control, plus evidence that it is implemented and effective.
• Often time-bound: They are frequently viewed as interim solutions until the prescribed control can be implemented, especially in brownfield OT environments.
• May combine multiple measures: Achieving equivalent protection may require a combination of administrative, technical, and physical safeguards.

Examples in manufacturing and OT/IT

• Using enhanced physical access controls, strict badge procedures, and video monitoring as a compensating control where legacy OT devices cannot support strong logical authentication.
• Implementing detailed manual review and approval workflows when automated segregation-of-duties enforcement is not yet available in an MES or ERP system.
• Relying on increased log review frequency and network segmentation when full endpoint protection cannot be installed on certain production systems.

Common confusion

• Not simply “extra” controls: Compensating controls are not just additional security layers; they are specific alternatives to a defined control that cannot be implemented as specified.
• Not necessarily permanent: They may be long-lived in brownfield plants, but they are often intended as temporary measures until systems can be upgraded.
• Different from defense-in-depth: Defense-in-depth refers to multiple, layered controls. A compensating control may be one of those layers, but its defining feature is that it intentionally replaces or stands in for a particular primary control.

Operational considerations

In practice, compensating controls influence how security and compliance are managed across OT and IT:

• Policy and procedures: Governance documents may explicitly describe when compensating controls are allowed and how they must be documented and reviewed.
• Validation and testing: Compensating controls are typically included in control testing, internal audits, and periodic effectiveness reviews.
• System integration: In MES/ERP and other manufacturing systems, compensating controls can show up as workflow steps, approvals, or monitoring activities tied to specific risks or regulatory requirements.