I have personaly tested this method in full on My AT&T Samsung Galaxy S4 ZOOM SM-C105AUCUMJ2 (4.2.2 Jelly Bean)
although it should be safe to use on any AT&T Samsung Galaxy S4 ZOOM running an android version prior to Kit-Kat
All Credit for this, "exellent completely safe", Root method goes to its creator k1mu
And please Know that it is only being shared with you via his explicit permission.
Please if you are not on an AT&T Galaxy S4 ZOOM, Fell Free to Read
but Do not seek help,instruction, or any other type of advice by posting in this thread as it is hard enough to find information about a specific device when the said device does not have a dedicated forum. Thank You for your Understanding in this.