The development of modern information technologies and innovations in all areas of life resulted in new threats to national and international security. Over the past decade, such threats as transnational cybercrime, cyber terrorism, the use of cyber weapons transformed from potential and hypothetical into real ones. Combating those threats has become a priority of the national security and defence sector. The article focuses on how the profound changes in the global security system, in combination with the evolution of the cyber threats, influenced the activities of the Security Service of Ukraine (SBU), turning the Service in a key element of the future national cyberse¬curity system. The author reasons for enhanced international cooperation and systematises practical examples of effective international efforts to counter cyber threats.