What should be used instead of the AWS AWSSSOMemberAccountAdministrator Managed Policy for least privilege?

What to use instead of the broad member-account admin policy

Replace the broad managed policy with a narrower, task-scoped policy that covers only the AWS IAM Identity Center administration actions the operator actually needs. For most teams, that means building role-specific access around provisioning, assignments, and review workflows rather than giving full member account administration. The goal is to make administration possible without granting the ability to broadly manage workloads, data, or unrelated account settings.

The practical decision is to separate access management from infrastructure administration. That usually means one set of permissions for identity and access tasks, and a different set for cloud resource operations. This avoids the common mistake of using a convenience policy because it is “close enough” and then inheriting every extra action it contains.

If you are trying to decide how narrow to go, start from the exact AWS IAM Identity Center tasks the person performs today and exclude everything else. The right replacement is often a custom customer-managed policy or a more limited AWS-managed alternative attached to a role with clearly defined scope, rather than a policy that assumes the user should administer the whole member account.

Why least privilege matters here

The main risk with the broad managed policy is privilege creep. A policy intended for administration can quietly become the default for day-to-day use, and once that happens, permission review becomes harder because the policy grants more than the job requires. In access-management terms, that increases the blast radius of any compromised session or mistaken approval.

This is also a governance problem, not just a permissions problem. Broad administration rights make it harder to prove separation of duties, harder to spot unused capabilities, and harder to tell whether a user is performing identity administration or using an overly powerful shortcut to reach unrelated resources. Reviewing the effective permissions regularly is what keeps the least-privilege design from decaying over time.

For teams already standardising identity controls, this is where AWS IAM Policies and Roles Guide is useful, because the policy choice only makes sense when you understand how AWS evaluates permissions, roles, and explicit deny.

How to scope the replacement policy

A strong replacement policy should map to job function, not job title. If the operator manages assignments and account access in AWS IAM Identity Center, grant those exact actions and leave out broader member-account administration, especially anything that would let the role alter unrelated infrastructure or privilege boundaries.

When the permission set is built well, the operator can complete the work without having standing authority over everything in the account. That design is easier to defend if you can point to the exact administrative workflow, the specific actions required, and the controls that prevent the role from drifting into general-purpose admin use.

Use IAM and IGA Basics when you need to distinguish entitlement administration from broader identity governance, and use Authorisation Models Guide when you need to decide whether role-based scope, attribute-based conditions, or a policy-based approach gives the cleanest least-privilege outcome.

Risk and Threat Considerations

A broad admin policy can turn a routine identity task into a high-impact access path. If the role is abused, misassigned, or attached to the wrong principal, the result is not just extra permissions, it is potential control over account administration, privilege assignment, and the settings that protect downstream cloud resources.

Failure mechanism: Overbroad administrative rights accumulate because the policy is easier to apply than a narrower design, then effective permissions are not recertified often enough to catch unused or dangerous actions.

Impact: A compromised or over-entitled administrator can expand access, weaken guardrails, or create a longer-lived privilege path than the business intended, which increases both incident impact and recovery effort.

Practitioner Guidance

What to verify: Confirm the policy actually matches the operational workflow, not the convenience of the current implementation. The safest test is whether every allowed action is needed for identity administration and whether any of them would be unacceptable if the role were compromised.

Common mistake: Teams often start with a broad managed policy and promise to tighten it later, but later rarely comes before the first access review. If the policy already exceeds the job, treat that as a design defect rather than an optimisation opportunity.

What good looks like: The role can perform only the required AWS IAM Identity Center administration tasks, a separate role handles infrastructure administration, and periodic review shows no unused privileges, no hidden escalation paths, and no overlap that breaks separation of duties.

Practitioner takeaway: Least privilege here means designing for the exact administrative task set, then proving over time that the effective permissions still match that task set as the environment changes.

Related resources from NHI Mgmt Group

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