For non specialists, Electromagnetic Pulse weapons (EMP) are fantasy weapons in science fiction movies. Interestingly, the susceptibility of electronic devices to electromagnetic interference has been advertised since the 90’s. Regarding the high integration of sensors and digital systems to control power-grids, telecom networks and automation infrastructures (e.g. Smart-grids, Industrial Control Systems), the intrinsic vulnerability of electronic devices to electromagnetic interference is of fundamental interest. In the context of IT Security, few studies have been carried out to understand how the effects may be a significant issue especially in the far-field region (distance between the transmitter’s antenna and the target with regard to the wavelength/central frequency). Most studies in Emanation Security (EMSEC) are related to near-field probing for side-channel and fault injection attacks assuming a close physical access to the targeted devices. In this paper, we propose a methodology to detect, classify and correlate the effect induced during the intentional exposure of analogue and digital systems to electromagnetic interference. Applying this methodology, the implication of the effects for the IT security world will be discussed with regards to the attacker profile needed to set-up a given scenario.