Navigation:  WebOffice > Best Practices > Securing the ArcGIS Server Objects

It is recommended to deactivate Web Access for the ArcGIS Server services used in WebOffice 10 R3 projects. This way users can only access ArcGIS Server services using WebOffice 10 R3 Client.

If other applications/clients should be able to make use of ArcGIS Server services as well then you could make use of ArcGIS Server built in security mechanisms.