Abstract
A different approach to the criminalization of attacks on computer systems together with inconsistent assessment of crime, differences in criminal proceedings, as a significant development in information technology to facilitate the production and distribution tools used to attack, raised the need for harmonization of the Member States of the EU which would enable an effective fight against this type of crime. Contribution shows the most common tools used to such attacks and the possibility of criminalization of handling in cases where the attack itself takes place, both in the EU criminal law as well as criminal law of the Czech Republic.