I have AT&T U-verse (Gigabit fiber product) at home and I believe that I an not vulnerable to public Internet attacks because I've configured my modem in pass-t

I have AT&T U-verse (Gigabit fiber product) at home and I believe that I an not vulnerable to public Internet attacks because I've configured my modem in pass-through mode. The AT&T pass-through is pretty weak and is really only a 1:1 NAT, not a bridge, but as far as I can tell, the modem does not answer to the Internet when configured in this mode.