A method, system, and computer program product for corporate portal security are provided, wherein security information corresponding to an external object imported into the corporate portal is automatically mapped from the object's native security system into the corporate portal system. For each external object imported, the corporate portal maps external users and external groups identified by the native security into corresponding portal users and portal groups according to a predefined mapping process, and stores the results in a manner that associates the external object with those portal users and portal groups. A plurality of database tables and maps determines the outcome of the predefined mapping process. Advantageously, when new external users or groups are added, they are detected by a synchronization agent which then automatically updates the database tables and maps. When custom group security configurations are desired, or when new domains are added, the portal administrator may manipulate a subset of the database tables and maps to achieve the desired configuration. Advantageously, manually intensive operations such as object-by-object security stampings, and/or re-manipulation of individual security settings associated with re-instantiated crawls, are avoided.