As far as I know - and please correct me if I'm wrong - Cain does not support WiFi cards. So if an attacker wants to perform ARP poisoning without being connected through Ethernet to the (router\switch) s\he must use an Aircrack adapter.
My question is, if the attacker somehow managed to plug his laptop to the router\switch, will s\he be able to use Cain and perform ARP poisoning and\or network sniffing against wireless clients which are connected to the router through WiFi?