Use a more limited, read-only role that only grants the exact workspace and incident access needed for the task. The Reader role is broader than most analysts require because it exposes a wide range of resource data. Least privilege should be enforced by assigning only the permissions needed for investigation, monitoring or reporting, and reviewing access regularly.
What to use instead of Microsoft Sentinel Reader
Use a narrower read-only role or a custom role that grants only the specific workspace, incidents, alerts and hunting data the analyst needs. For Azure environments, that usually means combining least-privilege Microsoft Sentinel access with a broader Azure access model so users can investigate without inheriting unnecessary resource visibility. NHIMG’s Azure RBAC and Service Principals Guide is a useful starting point for scope and role design.
The right replacement depends on the task. A SOC analyst who only needs to triage incidents should not get the same visibility as someone who manages data connectors, automation, or workspace configuration. Where the organisation uses Azure-native controls, Sentinel permissions should be paired with the right Azure role boundaries so access is limited to the workspace and data plane views required for investigation.
In practice, teams often overgrant by choosing a familiar built-in role because it is easier than designing a tighter one. That is exactly the situation least privilege is meant to prevent. NHIMG’s Privileged Access Management Guide and Just-in-Time Access and Zero Standing Privilege Guide both reinforce the same operational principle: access should be scoped to the job, not the platform’s default convenience model.
Why the built-in Reader role is usually too broad
Microsoft Sentinel Reader is designed for visibility, not for finely tuned investigation boundaries. That can be acceptable for some oversight scenarios, but it is often wider than an analyst needs because it exposes more resource data than the incident-response use case requires. When read access spans broader Azure resources or adjacent operational data, the role stops being a simple viewing permission and becomes a disclosure surface.
The practical issue is not just “can they read?” but “what else becomes visible if they can read it?” Incident work frequently needs only incident records, alerts, bookmarks and selected logs. If the role also reveals unrelated subscriptions, workspaces or supporting assets, it creates unnecessary exposure and makes segregation of duties harder to preserve.
That is why least privilege is better achieved with a custom or more limited role definition, rather than by accepting the broad Reader default. Microsoft’s own Azure guidance treats role scope as a first-class control decision, and NHIMG’s IAM and IGA Basics explains why access review and entitlement design matter just as much as the initial assignment.
How to choose the minimum useful access pattern
Start from the analyst workflow, not the product menu. Decide whether the user needs incident triage only, hunting only, reporting only, or operational administration as well. Then grant the smallest set of permissions that supports that activity, and separate those duties where possible. If the user needs to inspect workspace telemetry, make sure the access is constrained to the relevant workspace and time-bounded if the investigation is temporary.
When the task is investigative, read-only should mean read-only for the relevant scope, not “can browse everything.” When the task includes response actions, those should usually be separated into a different role or approved elevation path. NHIMG’s Authorisation Models Guide is useful when you need to decide whether simple RBAC is enough or whether a more granular policy model is needed.
For Azure-heavy deployments, it also helps to align Sentinel access with the surrounding Azure control model. The Microsoft Azure Security Guide gives a broader view of how RBAC, PIM and workspace-level controls fit together when analysts need access without unnecessary platform-wide visibility.
Risk and Threat Considerations
Overbroad Sentinel read access can expose incident data, supporting telemetry and wider Azure resource context than an analyst actually needs. That increases the blast radius of a compromised analyst account, a careless insider, or an overextended contractor role, because visibility can become a stepping stone to deeper environmental understanding.
Failure mechanism: The built-in Reader role grants more visibility than the task requires, so a single read-only assignment can leak operational details across resources, subscriptions or workspaces that are outside the intended investigation scope.
Impact: Excess visibility can support reconnaissance, accelerate lateral understanding of the environment, and make access reviews harder because the role appears harmless while still exposing sensitive operational context.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST SP 800-53 Rev 5, NIST CSF 2.0 and CSA Cloud Controls Matrix set the technical controls, while ISO/IEC 27001:2022 defines the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | AC-6 — Least Privilege | Sentinel access should be limited to task-needed permissions. |
| AC-3 — Access Enforcement | The question is about enforcing narrower read access than the broad Reader role. | |
| Recommendation — Apply AC-6 to grant only the minimum Sentinel permissions needed for each analyst task. Use AC-3 to enforce role boundaries that restrict Sentinel visibility to approved scopes. | ||
| NIST CSF 2.0 | PR.AA-05 — Least Privilege | Least-privilege assignment is the core control objective behind replacing Reader. |
| Recommendation — Implement PR.AA-05 by assigning only the access required for the Sentinel workflow. | ||
| ISO/IEC 27001:2022 | A.5.15 — Access control | Role replacement is an access-control design decision for Sentinel readers. |
| Recommendation — Define and enforce access-control rules that narrow Sentinel read scope to business need. | ||
| CSA Cloud Controls Matrix | IAM — Identity and Access Management | Cloud role design and scope limitation are IAM concerns in Azure/Sentinel. |
| Recommendation — Use IAM controls to right-size Sentinel roles and remove unnecessary visibility. | ||
Practitioner Guidance
What to prioritise: Define the exact analyst use case first, then map permissions to that use case rather than to the general idea of “read access.” If the user only needs incident triage, do not automatically include broader workspace or resource visibility.
What to verify: Check whether the role exposes telemetry, incidents and supporting Azure resource data that the user does not need. If it does, replace it with a narrower built-in role or a custom role and confirm the resulting access still supports the workflow.
Decision rule: If the user needs to investigate but not administer, choose the least broad read-only access that still allows the task to be completed. If the role would let them see substantially more than they can act on, it is too broad.
Practitioner takeaway: The goal is not simply “read-only access,” it is task-scoped visibility. In Sentinel, that usually means replacing broad default reading with a tighter role design and reviewing it as the investigation model changes.
Related resources from NHI Mgmt Group
- What should be used instead of the Microsoft Sentinel Contributor Role for least privilege?
- What should be used instead of the Azure Storage Blob Data Reader role for least privilege?
- What should be used instead of the Azure Reader and Data Access Role for least privilege?
- What should be used instead of the Azure Log Analytics Reader Role for least privilege?