Locked Shields is the largest international cyber security drill. It is regularly organised since 2010 by NATO CCDOE (Cooperative Cyber Defence Centre of Excellence), and the focus of the drill is a clash between two teams. The red team attacks the blue team, which plays the role of the defender. This year, the drill was attended by a total of 19 blue teams. The teams were charged with the defense of a diverse computer infrastructure of a fictional country’s military base consisting of different servers, numerous workstations, SCADA systems, etc. The defenders were to face attackers, whose objective was to damage, compromise, or completely take down the network or its elements, or at least to make things complicated for the defenders. In addition to the technical part, the drill is focused also on strategic decision-making, cooperation with the press and the handling legal matters. We were invited by colleagues from GovCert and assigned to the “Linux team”.