I don't think MITM is possible with LTE. My understanding is that it requires mutual authentication between the handset and tower/network. My guess is that 3G (

I don't think MITM is possible with LTE. My understanding is that it requires mutual authentication between the handset and tower/network. My guess is that 3G (UMTS and CDMA2000) is the same because they both use the 3GPP Authentication and Key Agreement (AKA) protocol. But yes, the access provider can still tap the line.