Category: Security Controls & Tailoring

Compensating Controls

Also known as: compensating security control, compensating security controls

Simply put

Compensating controls are alternative security measures an organization puts in place when it cannot implement a recommended or required control, often because of technical limitations, legacy systems, or business constraints. The substitute measure is intended to provide protection roughly equivalent to what the original control would have provided. They are a documented workaround rather than a way to ignore a security requirement.

Formal definition

A compensating control is a management, operational, and/or technical safeguard or countermeasure employed by an organization in lieu of a recommended or required security or privacy control, selected to provide equivalent or comparable protection for a system or organization. In NIST usage, compensating controls are implemented when the corresponding baseline control cannot be applied as specified, and they should be documented and justified as part of control tailoring. Practitioners should note that the acceptability, documentation, and approval requirements for compensating controls are framework- and authority-specific; the criteria and formal processes differ across frameworks (for example, NIST-based programs versus PCI DSS, which addresses compensating controls separately from its customized approach), and this entry does not cover the specific procedural or contractual requirements of any single program. Readers should verify current authoritative guidance for the applicable revision and framework.

Why it matters

Compensating controls are essential to real-world security and compliance programs because few organizations can implement every recommended or required control exactly as specified. Legacy systems, technical constraints, and business realities frequently make a baseline control impractical or impossible to apply as written. Compensating controls give organizations a structured, defensible way to maintain roughly equivalent protection rather than simply leaving a gap unaddressed. The key distinction an expert would insist on is that a compensating control is a documented and justified workaround, not permission to ignore a security requirement.

Because the acceptability, documentation, and approval of compensating controls are framework- and authority-specific, treating them casually can create both security and compliance risk. What qualifies as an adequate compensating control in a NIST-based program may not satisfy the separate treatment PCI DSS gives to compensating controls, which it addresses distinctly from its customized approach. An authorizing official, assessor, or auditor generally expects to see the rationale, the equivalent protection provided, and the justification captured as part of control tailoring, not an informal note. Undocumented substitutions tend to surface during assessments as findings.

A further caution is conceptual: compensating controls speak to compliance tailoring, but implementing a substitute measure does not by itself guarantee that the intended risk is meaningfully reduced. Organizations should evaluate whether the compensating measure actually delivers comparable protection to the control it replaces, and verify current authoritative guidance for the applicable revision and framework before relying on it.

Who it's relevant to

Information System Security Managers and Control Implementers

Those responsible for applying baseline controls encounter compensating controls whenever a required safeguard cannot be implemented as specified. They generally need to identify a substitute that provides comparable protection, document the rationale as part of control tailoring, and be prepared to explain why the alternative is adequate.

Authorizing Officials

Officials making risk-based authorization decisions must judge whether a proposed compensating control provides equivalent protection to the control it replaces. Because a documented workaround is not the same as ignoring a requirement, they generally expect clear justification before accepting the associated residual risk.

Assessors and Auditors

Those evaluating a system's control implementation review compensating controls to confirm they are documented, justified, and reasonably equivalent to the required controls. They should apply the acceptability and documentation criteria of the specific framework in scope, recognizing that NIST-based programs and PCI DSS treat compensating controls differently.

Organizations Operating Legacy Systems

Environments where a legacy system or process cannot be updated to meet a requirement often rely on compensating controls to maintain protection. These organizations should ensure the substitute measure genuinely delivers comparable protection and verify the applicable framework's requirements, rather than assuming any workaround is sufficient.

Inside Compensating Controls

Definition and Purpose

Compensating controls are alternative safeguards implemented when an organization cannot meet a baseline security requirement or control as prescribed. In NIST SP 800-53 and RMF contexts, they are generally used to provide protection equivalent or comparable to the originally specified control, and their use must typically be documented and justified rather than assumed acceptable by default.

Justification and Risk Basis

A compensating control generally requires a documented rationale explaining why the baseline control cannot be implemented as intended and how the alternative achieves comparable risk reduction. This justification is normally tied to the system's categorization and the risk tolerance of the authorizing official.

Documentation in the Security Plan

Compensating controls are commonly recorded in the System Security Plan (SSP) and associated artifacts such as a Plan of Action and Milestones (POA&M) where a gap remains. Documentation typically identifies the deficient control, the compensating measure, and the residual risk.

Authorization and Approval

The acceptance of a compensating control generally rests with the authorizing official (AO) or an equivalent approving authority as part of the authorization decision. In most implementations the compensating measure does not become valid simply by being implemented; it must be reviewed and accepted through the applicable governance process.

Framework-Specific Interpretations

The concept appears across multiple frameworks with differing terminology and expectations, and its treatment may vary between NIST-based RMF processes for federal and DoD systems and other contractual or regulatory regimes. Readers should confirm the specific requirements against the current authoritative text applicable to their environment.

Common questions

Answers to the questions practitioners most commonly ask about Compensating Controls.

Does implementing a compensating control mean a system is just as secure as if the original required control were in place?

No. Compensating controls are alternative measures selected when a baseline control cannot be implemented as prescribed, but their presence does not automatically mean the resulting security posture is equivalent. The organization generally must demonstrate that the compensating control provides comparable protection against the same threats the original control addresses. Compliance with a documented compensating control is not the same as achieving the security outcome, and an assessor or authorizing official may still judge the residual risk unacceptable. Readers should verify equivalence expectations against the applicable control catalog and agency tailoring guidance.

Can we adopt a compensating control on our own authority without approval from anyone else?

Generally no. In most implementations, a compensating control is not simply a self-selected substitution. It typically must be documented, justified, and accepted through the applicable governance process, which often involves the authorizing official (or an equivalent risk-acceptance authority) as part of a risk-based decision. The specific approval path depends on the framework and the system's categorization, so readers should confirm the required review and acceptance steps against current official sources for their environment.

How should a compensating control be documented so it holds up during an assessment?

Documentation generally should identify the specific baseline control that cannot be met, explain why it cannot be implemented as prescribed, describe the alternative measure being applied, and articulate how that measure provides comparable protection. It is common to record this rationale within the system security plan or equivalent authorization artifacts, along with any associated residual risk. The exact documentation format and required elements vary by framework and agency tailoring, so confirm the expected structure against the applicable authoritative guidance.

Where in the risk management process are compensating controls typically identified and evaluated?

Compensating controls are commonly considered during control selection and tailoring, and they are then evaluated during assessment and factored into the authorization decision. Because a compensating control substitutes for a baseline requirement, it is generally reviewed as part of the same risk-based process that supports an authorization decision rather than treated as a permanent exception. The precise placement within a given process depends on the framework in use, so readers should map this to their applicable process.

Are compensating controls a permanent solution or something that should be revisited?

Compensating controls are generally best treated as subject to ongoing review rather than as permanent fixes. Because authorizations are time-bound and subject to continuous monitoring, the continued adequacy of a compensating control should be reassessed as the environment, threats, and technical options change. Where a baseline control later becomes feasible to implement as prescribed, organizations often plan to transition to it. Readers should confirm review cadence and expectations against their applicable monitoring and authorization requirements.

How is a compensating control different from a plan of action to remediate a deficiency?

A compensating control is an alternative measure intended to provide comparable protection when a required control cannot be implemented as prescribed, whereas a remediation plan generally describes corrective actions and timelines to bring a deficient or unimplemented control into full compliance. The two can be related, but treating one as the other can misstate a system's posture during assessment and authorization. Readers should confirm how their applicable framework distinguishes these constructs and what artifacts each requires.

Common misconceptions

A compensating control can be self-selected and put in place without any approval.

In most implementations a compensating control requires documented justification and acceptance by the authorizing official or equivalent authority. Implementing an alternative measure does not by itself satisfy the requirement or transfer the accountability for residual risk.

Using a compensating control means the requirement has been fully satisfied and no gap remains.

A compensating control is intended to provide comparable protection, but it generally still represents a deviation from the prescribed baseline. Any residual gap is commonly tracked, and equating a compensating measure with full compliance can misrepresent the actual security posture.

Compensating controls are permanent once accepted.

Like the broader authorization they support, compensating controls are subject to continuous monitoring and periodic reassessment. Their continued adequacy should be revisited as conditions, threats, and applicable revisions of guidance change.

Best practices

Document each compensating control in the System Security Plan, clearly identifying the deficient baseline control, the alternative measure, and the rationale for equivalence.

Obtain and retain explicit acceptance from the authorizing official or equivalent authority rather than assuming an implemented measure is automatically valid.

Record any remaining gap and associated residual risk in a Plan of Action and Milestones or equivalent tracking artifact.

Reassess compensating controls under continuous monitoring, since acceptance is time-bound and conditions may change.

Verify the specific expectations for compensating controls against the current authoritative text of the framework applicable to your system, as interpretations may vary across NIST-based RMF, contractual, and other regimes.

Avoid treating a compensating control as full compliance; be explicit about where it deviates from the prescribed baseline and why the alternative provides comparable protection.