A host intercepts calls between two executables and determines whether the calls are permissible according to the host's security model which can be identify based, such as user identity based—for instance, mapping access rights within a specific data base user context to database object access. Such an identity security model differs from a common language runtime security model where managed code uses Code Access Security to prevent managed assemblies from performing certain operations. Managed assemblies registered with the host are host objects from the host's perspective for which access rights can be defined via security rules, such as are defined for individual user identities. A host can decide access between managed executables based on the host's identity based access rules by trapping any cross assembly calls and deciding whether such calls should proceed or be blocked from taking place based on the corresponding identity security settings.