This work reports on different types of current oscillations induced by chloride and fluoride species present in the Fe \ 0.75 M H2SO4 electrochemical system. Current oscillations can be used for the distinction between general and pitting corrosion. All halides influence the stability of the passive iron-oxide film. The oscillatory potential region shifts towards the passive state, at potentials higher than the Flade potential (E-F), In the halide-free system, current oscillations appear within a narrow potential region ( similar to30 mV) across the passive-active transition at E < E-F, where an unstable oxide film is formed. By adding relatively low concentrations of NaCl, complex current oscillations (period doubling, quadrupling or aperiodic) occur at E > E-F, where a stable oxide film is formed. These oscillations appear after a certain induction period of time. Similar behavior is observed by adding NaBr and NaI, but not NaF. In the latter case, where the HF is largely predominant while the concentrations of other ionic fluoride species is negligible, only monoperiodic current oscillations occur immediately after setting on the potential. Microscopic observations of the Fe surface reveal individual areas of attack in the presence of Cl-, contrary to HF. It is deduced that complex oscillations are associated with a localized attack of the passive oxide film by halides leading to pitting corrosion. On the other hand, monoperiodic oscillations are associated with a uniform dissolution by HF leading to general corrosion. To explain the difference between pitting and general corrosion, a point defect model is used for the description of the iron oxide film. This model takes into account the absorption of halides at local sites of the oxide as well as the formation of surface complexes between iron cations and halides.