In 2023, NÚKIB also recorded several DDoS attacks in which the attacker could not be identified. Number of declared DDoS attacks on European countries by NoName057(16) in 2023 PL 118 UA 99 LT 99 CZ 55 LV 55 IT 42 DE 41 EST One such example was the DNS NXDOMAIN campaign, its name based on the flooding attack technique it used. This campaign was notable for its lack of correlation with geopolitical events or the activities of the targeted organisations, leaving the motives behind the attacks unclear. Alongside the techniques and infrastructure used in this campaign, the only clues were the specific victim profile, as these attacks exclusively targeted Czech state institutions. 39 UK 36 SE 36 0 25 50 75 100 125 150 Figure 3 Ransomware attacks have been consistently recorded by NÚKIB since 2018. In June 2023 however, NÚKIB observed a noticeable increase in ransomware activities targeting strategically important Czech entities, prompting NÚKIB to issue an alert about the heightened risk. The most prominent actors in the statistics were the PLAY and LockBit gangs, mirroring global trends. Apart from those, NÚKIB registered numerous phishing campaigns carried out by both state-sponsored actors and cyber-criminal groups. While less important incidents more than tripled, important incidents decreased by a third. 2022 69 Less Important Cyber Incidents 217 74 Important Cyber Incident 43 Very Important Cyber Incidents 3 2 0 In June 2023 NÚKIB observed a noticeable increase in ransomware activities targeting strategically important Czech entities 12 2023 50 100 150 200 250 Figure 4: Evolution of the number of incidents registered by NÚKIB in 2022–2023 In terms of the severity of the incidents registered, positive developments were observed, with a year-on-year decrease in the number of important and very important cyber incidents despite a significant increase in the overall number of incidents (Fig. 4). The increase in the number and reduction of severity of registered incidents can be attributed to the repeated DDoS attacks against Czech targets, which are prominent in NÚKIB’s statistics but generally had no significant or long-term impacts.