A common failure is relying on manual collection and certification workflows across many disconnected systems. That approach makes reviews slow, inconsistent, and error prone, especially when legacy and modern platforms coexist. Organisations also miss unused or orphaned accounts if they do not maintain a complete view of permissions, roles, groups, and access relationships across the environment.
Why Hybrid Access Reviews Usually Break Down
Access reviews across cloud and on-premises systems fail when organisations treat certification as a spreadsheet exercise instead of a living identity governance problem. The hard part is not asking managers to approve access; it is building a complete, current picture of who has which permissions, through which roles, groups, service accounts, and inherited entitlements. In hybrid estates, that picture is fragmented by different control planes, naming conventions, and ownership models.
This is why reviews drift into superficial approvals, stale exceptions, and missed orphaned access. A useful benchmark is that 35.6% of organisations in The 2024 Non-Human Identity Security Report cite consistent access across hybrid and multi-cloud environments as their top challenge, which matches the practical reality that review quality depends on inventory quality. If the source records are incomplete, the attestation process only certifies uncertainty.
In practice, many security teams discover the failure only after access has already accumulated across teams, platforms, and exceptions that nobody owns end to end.
How It Works in Practice
Good access reviews start with aggregation, not approval. Organisations need a reconciled entitlement model that can pull identity data from cloud IAM, on-prem directory services, application-specific roles, privileged access tools, and any indirect access paths such as nested groups or federated roles. Without that normalization, reviewers see partial evidence and tend to approve what they recognise while missing what is inherited, dormant, or outside the current system of record.
The strongest programmes also separate human access from machine access. Hybrid environments often hide service accounts, API keys, automation identities, and delegated access in places that traditional access review workflows do not inspect well. That is where many reviews fail to detect standing privilege that no person actively uses but that still remains capable of reaching production systems.
Current guidance suggests that review quality improves when organisations define the unit of review carefully. Rather than asking, “Should this user have access?”, teams should ask which exact entitlement is being certified, what business function it supports, when it was last used, and whether the access is direct, inherited, or temporary. That distinction matters because cloud roles, application permissions, and directory groups do not behave the same way.
The operational sequence usually looks like this:
- Build a single entitlement inventory across cloud and on-premises sources.
- Resolve nested group membership, role inheritance, and cross-system mappings.
- Flag unused, duplicate, inherited, and orphaned access before reviewers see it.
- Route each entitlement to the right owner with enough context to make a decision.
- Record remediation evidence so revocations actually happen after the review closes.
That approach is materially stronger than asking managers to certify raw lists, especially when the same identity can hold different access models in different platforms. The OWASP Non-Human Identity Top 10 is relevant here because machine and service identities are frequently embedded in the same access review scope, and the NHI Lifecycle Management Guide helps explain why inventory, ownership, and rotation discipline are inseparable from review accuracy.
These controls tend to break down when legacy applications and cloud platforms use different entitlement semantics, because no one can reliably tell whether a review item represents direct access, inherited access, or a stale artifact of an old integration.
Where the Review Model Needs Extra Discipline
Tighter review scope often increases operational overhead, so organisations have to balance completeness against reviewer fatigue. The main tradeoff is that broader entitlement visibility creates more work up front, but it also reduces the chance that high-risk access is hidden inside legacy groups, shadow accounts, or automation credentials.
One common mistake is to assume that “more frequent” reviews will fix weak data. Frequency helps only after the entitlement model is trustworthy. Another mistake is treating cloud and on-premises access as if they can be certified with the same template, when in reality hybrid estates need different evidence for identity provenance, effective permissions, and last-use signals. Best practice is evolving, but the consistent pattern is that review programmes succeed when they are risk-based, system-aware, and supported by automated entitlement correlation rather than manual reconciliation.
For teams that also operate machine identities, the review process should explicitly decide what counts as active, what counts as dormant, and who can approve exceptions for non-expiring access. The 2024 Non-Human Identity Security Report is a useful reminder that many organisations still rely on static access patterns even while expecting dynamic environments, and that mismatch is exactly where hybrid reviews lose fidelity.
Practitioner takeaway: Hybrid access reviews are only as good as the entitlement graph behind them, so the real control objective is to certify verified access relationships rather than to close review tasks quickly.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 address the attack and risk surface, while CIS Controls v8 and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| CIS Controls v8 | 6 — Access Control Management | Hybrid reviews need inventory, review, and removal of unnecessary access. |
| 5 — Account Management | Orphaned and stale accounts are a core failure mode in hybrid review programs. | |
| Recommendation — Automate periodic access reviews and revoke accounts or entitlements that lack a current business need. Maintain authoritative account inventories and disable unused or orphaned accounts promptly. | ||
| NIST CSF 2.0 | PR.AC — Access Control | The question centers on governing who can access hybrid systems. |
| GV.RM — Risk Management Strategy | Review failures create governance risk through incomplete visibility and inconsistent certification. | |
| Recommendation — Correlate access paths across environments and enforce least privilege on all active entitlements. Prioritise review coverage for high-impact systems and align attestation frequency to access risk. | ||
| OWASP Non-Human Identity Top 10 | NHI-01 — Inventory and Ownership | Hybrid reviews often miss machine identities and inherited access that lack clear ownership. |
| Recommendation — Inventory every non-human identity and assign an accountable owner before certifying access. | ||
Related resources from NHI Mgmt Group
- What do organisations get wrong when they try to manage tenant access and custom roles across multiple CIAM vendors?
- What do organisations get wrong when they try to meet ISO 27001 and GDPR requirements manually?
- What do organisations get wrong when they try to make BYOD compliant across different device types?
- What do organisations get wrong about access reviews when they rely on approvals without decision context?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on September 9, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
