Control statement
[Organization-defined: ac-24_odp.01] to ensure [Organization-defined: access control decisions] are applied to each access request prior to access enforcement.
Discussion
Access control decisions (also known as authorization decisions) occur when authorization information is applied to specific accesses. In contrast, access enforcement occurs when systems enforce access control decisions. While it is common to have access control decisions and access enforcement implemented by the same entity, it is not required, and it is not always an optimal implementation choice. For some architectures and distributed systems, different entities may make access control decisions and enforce access.
Organization-defined parameters
These values must be resolved through the organization’s tailoring and governance process. Bracketed parameter references in the control text identify where a decision is required.
From control text to operational evidence
Use Access Control Decisions as a testable risk decision. Translate the official statement into accountable people, repeatable processes, configured technology, and evidence that demonstrates the outcome over time. In this family, pay particular attention to identity, authorization, least privilege, session boundaries, and access lifecycle governance.
Implementation workflow
- Define the control boundary, responsible owner, inherited portions, and systems or processes in scope.
- Resolve each organization-defined parameter before declaring the control implemented.
- Document how the implementation satisfies every clause of the official control statement.
- Collect evidence as a normal byproduct of operation rather than only before an assessment.
- Review exceptions, changes, and monitoring results on a risk-based cadence.
Evidence examples
- access approvals and entitlement records
- role and group configuration exports
- periodic access review results
- authentication and authorization logs
Common failure patterns
- standing privileges that outlive business need
- shared or orphaned accounts
- access rules implemented differently across systems
- approvals that cannot be traced to actual permissions
Questions practitioners should ask
- What risk decision is this control intended to support in this system?
- Which parts are implemented locally, inherited, shared, or not applicable—and what evidence supports that decision?
- Do the documented narrative, deployed configuration, operating process, and collected evidence agree?
- What event or threshold requires the implementation to be reviewed or changed?
Assessment objectives and methods
Show the assessment objective
[Organization-defined: ac-24_odp.01] are taken to ensure that [Organization-defined: access control decisions] are applied to each access request prior to access enforcement.
Examine
- Access control policy
- procedures addressing access control decisions
- system design documentation
- system configuration settings and associated documentation
- system audit records
- system security plan
- other relevant documents or records
Interview
- Organizational personnel with responsibilities for establishing procedures regarding access control decisions to the system
- organizational personnel with information security responsibilities
Test
- Mechanisms applying established access control decisions and procedures
Related controls
These relationships come from the official OSCAL catalog. They indicate useful dependencies or context, not automatic inheritance or equivalence.
Related defensive techniques
D3FEND maps this base control or one of its enhancements to the following defensive techniques. The ontology relation label is preserved and does not by itself prove implementation or effectiveness.
MITRE D3FEND™ and the D3FEND logo are trademarks of The MITRE Corporation. Bare Metal Cyber is not affiliated with or endorsed by MITRE.
Control enhancements
Enhancements add specificity, strength, or scope to the base control. Baseline badges show explicit selections in the official SP 800-53B OSCAL profiles.
AC-24(1) — Transmit Access Authorization Information
Transmit [Organization-defined: access authorization information] using [Organization-defined: controls] to [Organization-defined: systems] that enforce access control decisions.
Official discussion
Authorization processes and access control decisions may occur in separate parts of systems or in separate systems. In such instances, authorization information is transmitted securely (e.g., using cryptographic mechanisms) so that timely access control decisions can be enforced at the appropriate locations. To support the access control decisions, it may be necessary to transmit as part of the access authorization information supporting security and privacy attributes. This is because in distributed systems, there are various access control decisions that need to be made, and different entities make these decisions in a serial fashion, each requiring those attributes to make the decisions. Protecting access authorization information ensures that such information cannot be altered, spoofed, or compromised during transmission.
Organization-defined parameters (3)
Assessment objectives and methods
[Organization-defined: access authorization information] is transmitted using [Organization-defined: controls] to [Organization-defined: systems] that enforce access control decisions.
Examine
- Access control policy
- procedures addressing access enforcement
- system design documentation
- system configuration settings and associated documentation
- system audit records
- system security plan
- other relevant documents or records
Interview
- Organizational personnel with access enforcement responsibilities
- system/network administrators
- organizational personnel with information security responsibilities
- system developers
Test
- Mechanisms implementing access enforcement functions
Related controls
AC-24(2) — No User or Process Identity
Enforce access control decisions based on [Organization-defined: organization-defined security or privacy attributes] that do not include the identity of the user or process acting on behalf of the user.
Official discussion
In certain situations, it is important that access control decisions can be made without information regarding the identity of the users issuing the requests. These are generally instances where preserving individual privacy is of paramount importance. In other situations, user identification information is simply not needed for access control decisions, and especially in the case of distributed systems, transmitting such information with the needed degree of assurance may be very expensive or difficult to accomplish. MAC, RBAC, ABAC, and label-based control policies, for example, might not include user identity as an attribute.
Organization-defined parameters (3)
Assessment objectives and methods
- AC-24(02)[01]access control decisions are enforced based on [Organization-defined: security attributes] that do not include the identity of the user or process acting on behalf of the user (if selected);
- AC-24(02)[02]access control decisions are enforced based on [Organization-defined: privacy attributes] that do not include the identity of the user or process acting on behalf of the user (if selected).
Examine
- Access control policy
- procedures addressing access enforcement
- system design documentation
- system configuration settings and associated documentation
- system audit records
- system security plan
- privacy plan
- other relevant documents or records
Interview
- Organizational personnel with access enforcement responsibilities
- system/network administrators
- organizational personnel with information security and privacy responsibilities
- system developers
Test
- Mechanisms implementing access enforcement functions
Authoritative sources
Bare Metal Cyber is an independent educational publisher and is not affiliated with or endorsed by NIST. Official control requirements and interpretations remain with NIST and the responsible authorizing organization.