ASEE took part in Locked Shields 2026 for the first time, joining the Croatian national team in what is widely recognized as the world’s largest and most complex real-time cyber defence exercise. Organized by NATO’s Cooperative Cyber Defence Centre of Excellence (CCDCOE) in Tallinn, the exercise brought together 16 Blue Teams tasked with defending simulated national infrastructures against advanced cyber attacks.

The Croatian team, consisting of 135 members and supported by participants from North Macedonia, formed Blue Team 15. ASEE contributed to the team with experts from multiple disciplines: Dejan Mačinko, Rino Rodin, Luka Dragutin, Marin Mihajlović, and Ivan Vedak.

Contribution Across Technical and Strategic Domains

ASEE experts were actively involved in several key segments of the exercise, covering both technical and strategic aspects of cyber defence.

Within the Pentest Team, Dejan Mačinko, Rino Rodin, and Luka Dragutin were responsible for conducting security assessments across a complex system that simulated critical national infrastructure. This included a wide range of components, from public-facing web services to specialized and military systems. Their role was to identify vulnerabilities in real time, enabling other teams to respond quickly and implement appropriate mitigation measures.

At the same time, Marin Mihajlović contributed as part of the Web Team, focusing on the defence of web applications and services. His responsibilities included detecting and mitigating web-based attacks, configuring and tuning Web Application Firewalls, hardening web servers, managing TLS protocols, and analyzing logs. The dynamic nature of the exercise required rapid response times and a strong emphasis on automation and coordination with other infrastructure teams.

In addition to technical roles, Ivan Vedak participated in the STRATEX team, which focused on strategic-level response to cyber incidents and hybrid threats. This involved coordination with stakeholders across the public and private sectors, including military and national institutions. The team worked closely with legal and strategic communications units, aligning responses with regulatory frameworks such as DORA, NIS2, and GDPR, while managing crisis scenarios under strict time constraints.

Realistic Simulation of Modern Cyber Threats

Locked Shields is designed to simulate real-world cyber incidents, requiring teams to defend complex IT systems while maintaining service availability and responding to legal, strategic, and communication challenges. The exercise highlights the importance of cross-functional collaboration, rapid decision-making, and readiness in the face of evolving cyber threats.

Strengthening Cybersecurity Capabilities

ASEE’s participation in Locked Shields 2026 represents an important step in further strengthening its cybersecurity expertise and capabilities. By engaging in highly realistic and demanding scenarios, ASEE experts gained valuable hands-on experience and contributed to a coordinated international defence effort.

This milestone reflects ASEE’s ongoing commitment to advancing knowledge, supporting national and international cybersecurity initiatives, and continuously improving its readiness to address complex security challenges.