Category: Control Types and Framework

Compensating Control Measures

Also known as: Compensating Control, Compensating Security Control, Alternative Control

Simply put

A compensating control is an alternative security measure an organization puts in place when a preferred or recommended control cannot be deployed, often due to technical or business constraints. Its purpose is to reduce or mitigate the same risk that the primary control was intended to address. In practice, these measures aim to achieve a comparable level of protection through a different approach.

Formal definition

A management, operational, and/or technical safeguard or countermeasure employed in lieu of a recommended or primary security control when that control cannot be fully implemented. Compensating controls are intended to provide equivalent or comparable risk mitigation for a specific risk, and their suitability typically depends on scope, the auditor's or certification body's assessment, and the applicable criteria. Common examples in a financial or segregation-of-duties context include management review, independent reconciliations, dual authorizations, and automation of processes; some compensating measures (such as detective controls that operate after a transaction completes) are generally considered less desirable than preventive controls like separation of duties. In SOC 2 and ISO/IEC 27001 environments, whether a compensating control is accepted as adequate is an engagement-specific determination rather than a universal rule.

Why it matters

Compensating control measures matter because no organization can implement every recommended control exactly as prescribed. Technical limitations, legacy systems, resource constraints, or the realities of a small team can all make a preferred control impractical. Rather than leaving the underlying risk unaddressed, a well-designed compensating control allows an organization to mitigate that same risk through an alternative approach, preserving the intent of the original safeguard even when its literal implementation is not feasible.

In both SOC 2 examinations and ISO/IEC 27001 certifications, the presence of a credible compensating control can be the difference between a control gap being treated as an acceptable, mitigated condition and being treated as a deficiency. However, this is not automatic. Whether a compensating control is judged adequate is an engagement-specific determination that depends on the scope, the applicable criteria, and the professional judgment of the CPA firm conducting the SOC 2 examination or the accredited certification body assessing the ISMS. Organizations should document not only the compensating control itself but also the rationale for why the primary control could not be implemented and how the alternative achieves comparable risk mitigation.

A common practical context is segregation of duties, where a small organization may lack enough staff to separate incompatible responsibilities. Compensating controls such as management review, independent reconciliations, and dual authorizations can help address the resulting risk. It is worth noting, though, that many compensating controls are considered less desirable than the preventive control they replace: detective measures that operate after a transaction is complete catch issues later than a preventive control like separation of duties would have prevented them in the first place.

Who it's relevant to

Compliance and GRC managers

Those managing SOC 2 or ISO 27001 readiness need compensating controls when a recommended or primary control cannot be deployed due to technical or business constraints. Documenting the constraint, the alternative measure, and the rationale for comparable risk mitigation strengthens the position that a gap is mitigated rather than left open.

Auditors and certification body assessors

CPA firms conducting SOC 2 examinations and certification bodies assessing an ISMS must make engagement-specific determinations about whether a compensating control provides comparable risk mitigation. Their judgment depends on scope and the applicable criteria, and there is no universal rule requiring acceptance of any particular alternative.

Security engineers and control owners

Practitioners responsible for implementing controls often design compensating measures such as management review, independent reconciliations, dual authorizations, or process automation when a preferred control is impractical. They should weigh that detective compensating measures operating after a transaction completes are typically less desirable than preventive controls.

Finance and internal control teams

In smaller organizations where full separation of duties is not achievable, finance and internal control staff frequently rely on compensating controls to address segregation-of-duties risk. Understanding the trade-offs between preventive and detective approaches helps them select measures that best reduce the underlying risk.

Inside Compensating Control Measures

Definition

A compensating control is an alternative safeguard implemented when a primary or expected control cannot be applied, intended to reduce the associated risk to an acceptable level. It addresses the same control objective through a different mechanism rather than eliminating the requirement.

Risk-Based Justification

Compensating controls are typically supported by a documented rationale explaining why the primary control is not feasible, the residual risk involved, and how the alternative measure mitigates that risk. In most engagements this justification is informed by a risk assessment.

Role in SOC 2

Within a SOC 2 examination under the AICPA SSAE 18 standard, an auditor may evaluate whether a compensating control adequately supports the relevant Trust Services Criteria, most commonly the Security (Common Criteria) category, and any optional categories in scope. Whether the control is accepted depends on the auditor's professional judgment and the scope of the engagement.

Role in ISO 27001

Under ISO/IEC 27001, control selection is driven by risk assessment and documented in the Statement of Applicability. Where an Annex A reference control is not implemented as written, an organization may justify an alternative approach, provided the ISMS requirements in clauses 4 through 10 are satisfied and the certification body accepts the rationale.

Documentation Requirements

Compensating controls are typically evidenced through written justification, defined ownership, and supporting artifacts demonstrating operation. For a SOC 2 Type II, evidence would generally cover operating effectiveness across the review period, whereas a Type I addresses suitability of design at a point in time.

Scope and Boundaries

A compensating control only addresses the specific gap it is designed to cover. It does not extend the boundaries of a SOC 2 report or an ISO 27001 certificate, and its acceptance is limited to the controls, criteria, and period or scope defined in the engagement.

Common questions

Answers to the questions practitioners most commonly ask about Compensating Control Measures.

Does implementing a compensating control mean the original required control can be permanently ignored?

No. A compensating control is typically intended to address a specific gap or limitation where a primary control cannot be applied as designed, not to permanently substitute for a requirement. In most engagements, the compensating measure is evaluated on whether it achieves the same control objective, and its adequacy remains subject to the auditor's or certification body's judgment. It does not eliminate the underlying objective the original control was meant to satisfy.

Are compensating controls treated the same way under SOC 2 and ISO 27001?

Not identically. Under a SOC 2 examination, a CPA firm evaluates whether controls, including compensating ones, are suitably designed and, for a Type II, operating effectively over the review period against the applicable Trust Services Criteria. Under ISO 27001, the treatment of a control gap is generally addressed through the risk assessment and Statement of Applicability, where a control may be justified, adjusted, or its exclusion documented. The frameworks approach the concept differently, and satisfying one does not automatically satisfy the other.

How should a compensating control be documented so it holds up during an examination or certification audit?

Documentation typically describes the gap or limitation being addressed, the control objective the compensating measure is intended to meet, how it operates, who is responsible, and the evidence of its operation. In most cases, auditors and certification bodies look for a clear rationale linking the compensating measure to the objective. For ISO 27001, this rationale is often reflected in the risk assessment and Statement of Applicability; the specifics depend on scope and the reviewer.

What evidence is usually expected to show a compensating control is operating effectively?

For a SOC 2 Type II, evidence generally needs to demonstrate operation across the defined review period, so items such as logs, tickets, records of reviews, or sampled artifacts are commonly requested. A SOC 2 Type I assesses design at a point in time and typically relies on evidence of how the control is configured or intended to operate. The exact evidence depends on the auditor, the criteria in scope, and the nature of the compensating measure.

Who decides whether a compensating control is acceptable?

Acceptability is a judgment made by the assessing party. In a SOC 2 examination, the licensed CPA firm evaluates whether the compensating measure supports the applicable criteria. In an ISO 27001 certification, the accredited certification body assesses whether the approach is consistent with the ISMS requirements and the organization's risk decisions. Because outcomes depend on the reviewer and scope, an organization generally cannot assume a compensating control will be accepted in advance.

How does a compensating control affect the scope and limitations of the resulting outcome?

A compensating control does not extend the boundaries of what an outcome covers. A SOC 2 report attests only to the controls and the period covered and does not guarantee freedom from breaches, and an ISO 27001 certificate covers only the defined scope of the ISMS. A compensating measure operates within those existing boundaries, so its presence should be understood in the context of the scope and period already defined for the engagement.

Common misconceptions

A compensating control lets you skip a requirement entirely.

A compensating control does not remove the underlying control objective; it addresses that same objective through an alternative means. The organization still needs to demonstrate that the risk is reduced to an acceptable level, and acceptance depends on the auditor or certification body.

If a compensating control is accepted for SOC 2, it automatically satisfies ISO 27001, and vice versa.

The two frameworks are distinct, SOC 2 is an attestation examination performed by a licensed CPA firm resulting in a report, while ISO 27001 is a certification issued by an accredited certification body against a management system standard. Mapping between them is partial, so a compensating control justified under one does not automatically satisfy the other.

Once a compensating control is documented, it needs no further evidence.

In a SOC 2 Type II, the control's operating effectiveness typically must be evidenced across the defined review period, and under ISO 27001 the ISMS is subject to ongoing assessment. Documentation alone, without evidence of operation, is generally insufficient.

Best practices

Document a clear risk-based rationale for each compensating control, explaining why the primary control is not feasible and how the alternative reduces residual risk to an acceptable level.

Tie each compensating control back to the specific control objective it addresses, such as a relevant Trust Services Criterion for SOC 2 or an Annex A reference control reflected in the Statement of Applicability for ISO 27001.

Engage the auditor or certification body early, since acceptance of a compensating control depends on their professional judgment and the defined scope of the engagement.

Retain evidence of ongoing operation, not just design, particularly for a SOC 2 Type II where operating effectiveness is assessed across the review period.

Assign clear ownership and review cadence for each compensating control so it is maintained and re-evaluated as risks and scope change.

Avoid assuming cross-framework equivalence, reassess and, if needed, re-justify compensating controls separately for SOC 2 and ISO 27001 rather than relying on acceptance under one to carry over to the other.