The article is devoted to study of information security as a challenge of modern development of information and computer technologies. It was found that achievement of a satisfactory level of information security, which is a state of safety of balanced important interests of an individual, society and state against internal and external threats in the information sphere, is possible based on economic, organizational, technical, legal, psychological and other methods. Existing threats to the information security in Ukraine have been identified. The concept and essence of hybrid war as one of the threats to protection of information interests of an individual, society and the state are considered separately. A conclusion was made about the expediency of supplementing the Information Security Doctrine of Ukraine with such a threat as a hybrid war, which actually takes place in the east of the country. A system of information security components in Ukraine has been disclosed, among which a particular attention has been paid to the Ministry of Information Policy of Ukraine and the State Agency for Electronic Governance of Ukraine. In order to improve the mechanism of protection of the information space of Ukraine, it is proposed to differentiate at the legislative level the concepts of “information security” and “cybersecurity”, since their understanding is the basis for the formulation and implementation of the state information policy, improve international cooperation between states to exchange experience, as well as to involve general public to protect the information space.