Experimental setups used in electromagnetic compatibility tests can be used as platforms for fault injections. Faulting an equipment is a means for a malevolent attacker to extract secret information. Compared to other fault injection setups, those based on EMC tests enjoy three advantages: non-invasivity, absence of synchronization, and frequency selectivity. This injection technique therefore allows for remote attacks from attackers that has little knowledge about the targeted equipment. To assess the potential of this attack, a characterization of its effects is needed. This is the purpose of this paper. In particular, we use an advanced setup and propose a method to find the disturbance's parameters, power and frequency, leading to the optimum attack.