The world we are living in become more and more interacted and this is in close connection with the development of information and communication technology. This growing interdependence generates fuel for development but is also a disadvantage if we take into account that most of public institution or private companies are totally dependent by cyber systems in fulfillment of their mission. Internet is a critical infrastructure, and its disruption could generate substantial losses and great security risks, distressing a lot of citizens and industries. Lately the cyber threats became more and more serious, frequent and sophisticated. Having no borders the cyber security risk must be managed at international level, through cooperation of all actors involved. That is why this essay tries to identify part of the global cyber security issues, the main cyber threats and their implications for millions of people depending on the digital infrastructure of a nation, which are the vulnerabilities and how to better react in countering the cyber threats.