Information and Communication Technologies and Internet networks are present in all aspects of social reality and are essential elements in research, development and innovation centers (R&D&I). Cyber-security is crucial for the progress of the research activities developed in these centers, especially given the exponential growth of cyber-attacks and incidents. The present study aims to assess from a socio-technical approach, how a serious cyber-attack on a Spanish research center has affected staff’s perceptions of information and communication systems (ICT) security. This study employed a mixed-methods research strategy, combining quantitative and qualitative methods to provide a comprehensive and nuanced understanding of ICT security perceptions among employees. First a quantitative scale was administered to 1,321 employees 3 years before the cyber-attack and 4 months afterward, to measure ICT security perceptions. Then, qualitative techniques (semi-structured interviews, focus groups, and micro-ethnography) were applied to gain a deeper understanding of the arguments underpinning cyber-security at the center after the attack. The results show that the event had an impact on employees’ perceptions, increasing the perceived importance of ICT security, with positive behavioral changes noted, but with doubts about their sustainability over time. Also, the need for cyber-security governance was critically contrasted with organizational reality. Finally, the compatibility of science and cyber-security was a central dilemma, which seems to confront antagonistic poles (research and security ICT) and justify the non-compliance with security protocols by part of the staff.