Catechism of the Catholic Church §1237 — excerpt
Since Baptism signifies liberation from sin and from its instigator the devil, one or more exorcisms are pronounced over the candidate. the celebrant then anoints him with the oil of catechumens, or lays his hands on him, and he explicitly renounces Satan.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.