Containerized security for managed content

Containerized security is disclosed. An indication is received that a content item included in a body of managed content is associated with a container. A security measure is associated with the content item, based at least in part on the association of the content item with the container, that causes access to the content item by a user who is not associated with the container but who otherwise would have access to the content item within the body of managed content to be denied.