This research topic is focused on the design and implementation of models and mechanisms to prevent, detect and contain attacks and intrusions to computer networks. One research area is devoted to the design and implementation of models that define the legal behavior of critical programs to detect their malicious usage by remote attackers; another research area defines models and tools to prevent and contain distributed attacks to computer systems. In this field, a new and promising topic is focused on the design and implementation of secure models and tools to contain the spreading of viruses and worms on mobile phones.