How fan we capture unencrypted packets from the network? I thought you had to run tcpdump or something like that to be able to do that. But you won't be able to run tcpdump if you don't have access to the interface (source or destination), no?
I'm speaking in the context of the parent conversation ("unencrypted WiFi packets"). On wireless networks, all devices share the same "wire", so to speak. Normally that traffic is useless when captured due to encryption, but that's not the case on unencrypted (i.e. public) WiFi.
It doesn't matter if the wifi is encrypted or not. All that matters is that you share the network with an attacker. You can ARP poison just fine, encrypted or open, wifi or wired.
