Intervention against cyberbullying and other risks associated with the misuse of ITC and social networks is an important social demand. The 'Asegúrate' Program tries to support teachers in this intervention. This research shows the impact of the program among those that have shown to be less sensitive in other studies: cyber-aggressors. Concretely, the impact of the program on the prevalence of aggression in cyberbullying and bullying, sexting and abusive use of the Internet and social networks are analyzed. The evaluation of the program was carried out with a sample of 479 students (54.9% girls) of Compulsory Secondary Education (age M=13.83. SD=1.40) through a quasi-experimental methodology, with two measures over time. The instruments used were the "European Cyberbullying Intervention Project Questionnaire", the "European Bullying Intervention Project Questionnaire", the "Internet Related Experiences Questionnaire" and two items about sexting involvement. The results show that the involvement in cyber aggression, sexting, and intrapersonal dimension of abusive use of Internet and social network increases without intervention, whereas it diminishes when the intervention is carried out. Moreover, a significant decrease in the aggression and cyber aggression among cyber aggressors is evidenced. Thus, 'Asegúrate' Program is effective for decreasing the prevalence of aggressions and cyber aggressions as well as the involvement in other phenomena considered cyberbullying risk factors.