A cyberattack describes an attack on important computer networks from the outside. As a rule, networks are part of larger infrastructures that are relevant to civil society. In addition to production facilities and energy supply companies, these can also be banks, government institutions or universities. A cyberattack is generally carried out by professional hackers. It has often turned out that hackers have already had access to the network for a longer period of time before they were discovered or drew attention to themselves. Victims of large cyberattacks include the German Federal Police (2011), various banks (2013, 2016), and the Ukrainian electrical grid (2015).