Microsoft 365 Copilot Governance: Restricting Oversharing with Restricted Site Access (RSA) Policies | LoveSharePoint
1. Executive Summary & Problem Analysis
When Microsoft 365 Copilot is deployed across a tenant, it accesses any document the prompting user has permissions to view. If historical SharePoint sites were improperly shared with 'Everyone except external users', Copilot will inadvertently surface confidential salary, acquisition, or layoff documents in conversational answers.
An automated security governance agent that evaluates overshared site collections, applies Microsoft 365 Restricted Site Access (RSA) policies, and restricts access exclusively to members of a designated Entra ID security group, preventing Copilot oversharing even if individual files have broader permissions.
In large-scale Microsoft 365 enterprise tenants spanning tens of thousands of active site collections, manual administration and ad-hoc scripting introduce severe compliance vulnerabilities, operational latency, and unexpected cloud license expenses. When security baselines and storage quotas are managed reactively, organizations encounter compounding technical debt: unmonitored version trees degrade Microsoft 365 Copilot semantic search indexing, expired application secrets halt overnight ETL workflows, and orphaned guest sharing links violate ISO 27001 and GDPR compliance frameworks.
This technical guide by LoveSharePoint Team establishes an automated, auditable engineering architecture designed to enforce governance baselines at tenant scale while minimizing administrative overhead.
