By using an SDR receiver it is possible to capture, demodulate and decode the NFC signal between the card and the reader. Currently, detection and decoding is implemented for:
UCSniff is a VoIP & IP Video Security Assessment tool that integrates existing open source software into several useful features, allowing VoIP and IP Video owners and security professionals to rapidly test for the threat of unauthorized VoIP and Video Eavesdropping. Written in C/C++, and available on Linux and Windows, the software is free and available for anyone to download, under the GPLv3 license.