Elastic medium stable kql

Entra ID Guest Account Promoted to Member

Identifies Entra ID user accounts converted from Guest to Member type via an Update user operation. A Guest-to-Member conversion grants the account full directory read access, removes external-identity Conditional Access restrictions, and makes the account indistinguishable from an internal employee. An attacker who compromises a guest account and promotes it to Member type gains persistent tenant access without triggering role assignment alerts.

View Source

Detection Logic

data_stream.dataset: "azure.auditlogs" and
azure.auditlogs.operation_name: "Update user" and
azure.auditlogs.properties.target_resources.*.modified_properties.*.display_name: "UserType" and
azure.auditlogs.properties.target_resources.*.modified_properties.*.old_value: *Guest* and
azure.auditlogs.properties.target_resources.*.modified_properties.*.new_value: *Member* and
event.outcome: (Success or success)

False Positives

  • B2B collaboration migrations where external users are intentionally promoted to full membership. Organizational restructuring that converts former contractors to permanent employees in place.

Field Validations

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