By default, OSPF must be configured on an interface for direct interface addresses to be advertised as interior routes. To advertise the direct interface addresses without actually running OSPF on that interface (adjacencies are not formed and hello packets are not generated), you configure that interface as a passive interface.
Read more at https://www.juniper.net/techpubs/en_US/junos11.4/topics/example/ospf-passive-interface-configuring.html#tkV8FoOXCHp5dck2.99