The objective is to become aware of dangers which development represents on Internet. There is no inviolable system; the skirting of a protection is always possible. If the problem does not come from the code, it will come from a server fault (or vice versa). This article does not claim to be exhaustive on a subject as vast as is the securisation of a Web server. In particular, the securisation on the system level (firewall, access rights...) which was not approached although it is essential.