The Chief of Staff of the Luxembourg Army has reported that Luxembourg took part in the largest and most complex international live-fire cyber defence exercise for the first time at the end of April 2021.

"Locked Shields" is an annual exercise organised by the NATO Cooperative Cyber Defence Centre of Excellence (CCDCOE). Luxembourg was part of an international team with counterparts from the other Benelux countries. Due to the COVID-19 pandemic, team members were not together in the same location but, despite being physically spread across three different countries, the Benelux team members cooperated well and achieved a remarkable result in their first appearance as a tri-nation team.

The Luxembourg Blue Team delegation consisted of GovCERT/MilCERT, Restena and with its Cybersecurity Competence Center department. Blue Teams are the main beneficiaries of the training provided by the Locked Shields exercise. Their mission was to defend a pre-built network against the Red Team attacks. The Red Team's mission was to compromise or degrade the performance of the systems under protection by Blue Teams.

Luxembourg's Computer Incident Response Center (CIRCL) of was also part of the organising team (Yellow Team). As a Yellow Team member, CIRCL contributed to setting up instances of the Open Source Threat Intelligence and Sharing Platform "MISP". works very closely with the Luxembourg Army and is the main contributor for and driver behind the MISP platform.

The Locked Shields 2021 exercise was an opportunity to develop and deepen competence of all Blue Team participants and helped CIRCL as yellow team member gain valuable input on how to further develop the MISP platform, particularly during a cyber incident.

Luxembourg is set to take part in the next edition of Locked Shields 2022. In the meantime, it will be integrating the lessons learned into internal procedure and policy.