As the name suggests, a cloud access security broker (CASB) manages access between enterprise endpoints and cloud resources from a security perspective. CASBs can be deployed on-premises or in the cloud; as a hardware appliance or software-only, as a proxy, reverse proxy, or through specific APIs.

Enterprises have untold numbers of endpoints, both managed (corporate-owned devices) and unmanaged (devices owned by employees or third-party contractors). Endpoints can be on-premises or remote. And endpoints can include internet of things (IoT) devices.