Today, the technological world is increasingly affected by cyber-attacks and cybercrime, and, at the same time, it is proliferating. Consequently, some ways of protection become essential. As a result, one of the most critical countermeasures is the detection of these cyber-attacks. Each attack leaves traces in the target system in different forms. In this respect, the purpose of this thesis is, firstly, a deeper analysis of various monitoring and logging techniques, the source information they process, and the solutions which better can detect most attacks, second allowing a better comprehension of what is going on through the creation of security alerts.