What should be used instead of the Google Cloud Service Account Creator Role for least privilege?

What to use instead of the Google Cloud Service Account Creator Role

For least privilege, replace the broad Service Account Creator role with a narrower predefined role or a custom IAM role that grants only the service account actions the operator actually needs. The practical test is whether the role can create, bind, impersonate, or modify service accounts beyond the intended workflow. If it can, it is too broad for routine delegation.

That distinction matters because service account administration is often bundled with other IAM capabilities that are convenient but not always necessary. A narrower role keeps the change surface small, while a custom role lets you separate everyday administration from privileged exceptions such as policy binding changes, impersonation setup, or key-related operations.

When you design the replacement, start from the exact task. If the operator only needs to view service accounts, grant read-only access. If they need to create or manage a specific subset, grant only those permissions and keep broader IAM changes behind approval. The aim is not to eliminate administration, but to avoid handing out a role that can be reused for unrelated access expansion.

Why narrower IAM scopes are better than broad creator access

The Service Account Creator role is attractive because it reduces friction, but broad creation rights can become a privilege-escalation path. In practice, the ability to create a service account is often tied to later steps such as attaching roles, generating credentials, or reusing the new identity in workloads and automation. That is why least privilege should be expressed as task-based access, not convenience-based access.

AGoogle Cloud IAM and Service Accounts Guide explains the role and policy patterns that help teams separate basic administration from broader service account governance. For real-world failure modes, a Kubeflow cryptomining attacks 2020 case shows how service account exposure can be abused once an attacker reaches an execution environment. The lesson is that service account permissions should be treated as a control boundary, not just an administrative convenience.

Custom IAM roles are especially useful when a team needs a narrow, auditable permission set that does not map cleanly to a predefined role. That lets you preserve separation of duties: one group can request or approve the change, while another can operate within the limited scope. In larger environments, this is usually stronger than trying to find a single built-in role that fits every workflow.

How to structure the safer replacement role

Build the replacement around the minimum permissions needed for the operator's normal job, then review whether any permission is actually required for delegation, impersonation, or policy changes. If the answer is no, do not include it. If the task is occasional rather than routine, treat it as elevated access rather than permanent access.

Privileged Access Management Guide is the right companion when you need to decide whether the operator should have standing access at all. Where the task is tied to service account lifecycle, NHI Lifecycle Management Guide is useful for aligning creation, rotation, review, and offboarding with the same access model. For broader identity governance patterns, IAM and IGA Basics helps place service account permissions inside provisioning and access review processes.

In Google Cloud terms, the better pattern is usually to split concerns: one role for reading or listing service accounts, another for controlled creation, and a separate approval path for higher-risk actions such as binding, impersonation, or long-lived credential management. That separation makes review easier and limits the blast radius if an operator account is misused.

Risk and Threat Considerations

Broad service account creation rights can become a pathway to unauthorized access, persistence, or lateral movement if an operator account is compromised. The risk is not just that a new service account can be created, but that it may later be paired with permissions or credentials that outlive the original business need.

Failure mechanism: An attacker or over-permissioned operator uses creator access to establish a new identity path, then attaches broader access, creates credentials, or reuses the account for actions that bypass normal scrutiny.

Impact: The result can be privilege escalation, hidden persistence, and harder-to-audit access paths across projects or environments, especially if service account policy changes are weakly reviewed.

Practitioner Guidance

What to verify: Confirm exactly which service account actions the operator needs, then remove anything that is not required for the day-to-day workflow. If the role can create identities but the job only needs visibility or limited administration, the permission set is already too broad.

Decision rule: If an action can change access scope, attach credentials, or enable future reuse, put it behind approval or a separate privileged path. If it is routine and low risk, keep it in the narrow role; if it is occasional or high impact, make it just-in-time or exception-based.

Practitioner takeaway: Least privilege here means separating service account administration from service account power, because the first is operational and the second can quickly become an access-expansion mechanism.

Related resources from NHI Mgmt Group

• What should be used instead of the Google Cloud Organization Administrator Role for least privilege?
• What breaks when Google Cloud VM instances use the default service account instead of a least-privileged identity?
• What are the security risks of assigning the Google Cloud Service Account Token Creator Role?
• Google Cloud Service Account Creator Role (roles/iam.serviceAccountCreator)