there is no app perse, but as mentioned there is a rerouting service, i think the paid service is called trucaller or something, it reroutes the call through lines used by bank etc. and you see the callerID this way. The rerouting of all also reveals spoofed numbers, which seems to be the biggest problem (I used to administer a phone complaint site and 90% of complaints came from spoofed numbers). The unknown CID you're seeing may be spoofed CID as well, so...