Electromagnetic attacks, which in fact exploit essentially the magnetic field generated by ICs, are commonly used by adversaries to retrieve secret information manipulated by integrated circuits. Due to the increasing resolution and effectiveness of EM equipment used to perform these attacks, it is becoming increasingly difficult to design secure circuits robust enough to resist these attacks. The contribution of this paper is threefold. First, it describes a simulation flow of the magnetic field radiated by ICs. The introduced flow is based on an industrial voltage drop tool: ANSYS RedHawk. Second, it introduces a methodology to localize the root cause of leakages in ICs as well as EM hotspots, i.e. positions above the IC surface where an adversary can place its probe to capture secrets. The latter contribution is based on the concept of noise to add which is introduced in this paper in order to overcome the absence of noise in simulations (noise which is omnipresent in practice) that limits their interpretability. Finally, the paper demonstrates the soundness of the proposed solution by confronting simulation results with measurements.