Treat segregation of duties as the preventive gate and user access reviews as the corrective loop. SoD should stop conflicting access during provisioning, while reviews should verify that remaining access still matches the role. The controls only work well together when they share the same identity data, remediation ownership, and evidence trail.
Why This Matters for Security Teams
segregation of duties and user access review solve different problems, and treating them as interchangeable weakens both. SoD is a preventive control: it blocks toxic combinations before access is granted. Access reviews are corrective: they catch privilege drift, inherited access, and exceptions that survive operational change. The risk is not just over-permissioned users. The same pattern appears in Non-Human Identities, where service accounts, API keys, and automation often accumulate access faster than teams can review it. NHI-specific guidance in the Ultimate Guide to NHIs shows how common excessive privilege remains, and the OWASP Non-Human Identity Top 10 treats weak governance and permission sprawl as core failure modes.
The practical question is not whether to use both controls, but how to make them reinforce each other. That means one identity record, one ownership model, and one remediation path. If SoD flags a conflict and the review process does not know who can fix it, the control becomes a report instead of a safeguard. In practice, many security teams only discover that gap after an access certification has already approved an entitlement that should never have existed.
How It Works in Practice
The strongest operating model is to use SoD rules at provisioning time and access reviews at steady-state intervals. SoD should evaluate the requested role, account, or entitlement against incompatible duties before approval. Reviews should then validate whether the live access still matches job function, project need, and exception status. This is especially important for NHIs, because static permissions on long-lived accounts are difficult to see, easy to forget, and often more powerful than intended. NHIMG research in the Ultimate Guide to NHIs — Key Challenges and Risks and the NHI Lifecycle Management Guide highlights why lifecycle ownership and revocation discipline matter as much as approval logic.
- Define SoD rules for high-risk combinations, such as request-and-approve, create-and-delete, or deploy-and-audit.
- Bind every entitlement to a named owner, a business purpose, and a review cadence.
- Use the same identity source for provisioning, review, and remediation so findings do not drift across systems.
- Route violations to the team that can actually revoke, reassign, or reclassify the access.
- Keep evidence of both the preventive decision and the corrective follow-up for auditability.
For implementation detail, pair IAM workflow controls with identity governance, PAM where elevation is involved, and policy language that can be interpreted consistently across systems. The OWASP Non-Human Identity Top 10 is useful here because it frames privilege excess, secret handling, and weak lifecycle controls as operational risks, not just configuration issues. Current guidance suggests that the review should not simply reapprove what already exists; it should test whether the access still fits the role and whether the original SoD exception is still justified. These controls tend to break down when entitlement data is fragmented across HR, IAM, PAM, and cloud consoles because no single owner can confirm what should be removed.
Common Variations and Edge Cases
Tighter SoD often increases review overhead, requiring organisations to balance stronger prevention against slower provisioning and more exception handling. That tradeoff is unavoidable in shared-admin environments, engineering platforms, and cloud operations where a single person may legitimately need multiple capabilities during an incident or release window. Best practice is evolving, but a common pattern is to allow temporary exceptions with explicit expiry, rather than permanently weakening the SoD rule.
There is also a difference between human access and NHI access. For service accounts and automation, role-based review alone is often too coarse, because the account may not map cleanly to a job function. In those cases, reviewers should validate workload purpose, token scope, secret lifetime, and whether the account can be replaced by a narrower, short-lived identity. The 52 NHI Breaches Analysis is useful for understanding how privilege creep and weak ownership show up in real incidents. Where the environment is highly dynamic, current guidance suggests combining SoD with just-in-time elevation, rather than relying on permanent role assignments.
That said, there is no universal standard for how granular SoD must be in every organisation. Mature teams start with a short list of high-impact conflicts, tie reviews to the same policy set, and measure how quickly exceptions are removed after they expire.
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 NIST CSF 2.0 and NIST AI RMF set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-03 | Addresses excessive privilege and lifecycle control for non-human identities. |
| NIST CSF 2.0 | PR.AC-4 | Access approvals and reviews map directly to controlled privilege management. |
| NIST AI RMF | Supports accountability and governance where autonomous workloads complicate access decisions. |
Enforce least privilege with periodic reviews and remove access that no longer fits the role.
