Yes, I think you can cite in a way that is ethically correct. If you claim c which is mentioned in book C, but you know this from book B which references C, you can cite:
AuthorC: "C", PlaceC, TimeC, cited in AuthorB: "B", PlaceB, TimeB.
even without ever holding book C in your hand. You delegate the responsibility for correctness of the information c to B.
See also: http://english.stackexchange.com/questions/148878/phrase-cited-afterhttps://english.stackexchange.com/questions/148878/phrase-cited-after as well as http://www.reading.ac.uk/library/finding-info/guides/lib-citing-cited-ref.aspx
The phrases "cited in" and "cited by" are more common, albeit you may find "cited after" in some cases.
With regards to ethics, using the abovementioned method of citing you do avoid being dishonest and deceitful. However, the professor marking your scientific text may still think that you have cut a corner by not tracking down the actual source yourself.
Still hoping my answer helps,
Ned64.
