OneLake is Microsoft Fabric’s unified data lake: a shared storage layer where files, tables, and analytical data can live across the platform. Instead of each workspace or service keeping its own isolated copy, OneLake provides a common location that Fabric apps, pipelines, notebooks, and AI workloads can read from and write to.
Security-wise, that centralization is powerful and risky. OneLake can simplify governance, but if permissions are too broad, a single mistake may expose data to many downstream workloads at once. In attacks, adversaries often target shared storage because it can contain sensitive datasets, credentials in misused files, or high-value business context for later exfiltration. Defenders should treat OneLake as a high-trust asset: apply least privilege, monitor unusual reads and bulk exports, review sharing settings, and separate sensitive data with clear access boundaries. The more applications and agents rely on OneLake, the more important identity, auditing, and policy enforcement become.