A team from the Czech Republic has won Locked Shields 2017, the world’s largest and most complex international live-fire cyber defence exercise. It is organised by the NATO Cooperative Cyber Defence Centre of Excellence (CCD COE) and was held on 24-28 April in Tallinn, Estonia.

The network defence exercise focuses on training security experts from all over the world – who protect national IT systems on a daily basis – in cutting-edge cyber technologies, according to a press release.

During the event, teams must maintain the networks and services of a fictional country as it faces thousands of live cyber attacks. According to the release, this includes “handling and reporting incidents, solving forensic challenges, and responding to legal and strategic communications.”

Depending on the scenario, teams must defend against severe attacks on electric power grid systems, drones, military command and control systems and other operational infrastructure, in real-time.

A total of 800 participants from 25 countries took part in the exercise, with the Czech team performing the best in the scenario challenges. The Estonian and NATO teams came in second and third, respectively, at the exercise.

Meanwhile, the UK team was best at handling strategic communications, Germany at forensic challenges, and the NATO team at legal exercises.

This year, a new “strategic track” was introduced to the exercise to train policy and legal officers in making decisions during intense cyber attacks, the release said.

“The exercise was particularly challenging for all participants this year due to the increased scope and size of specialised systems involved,” Aare Reintam, Technical Exercise Director, NATO CCD COE was quoted as saying.

“The winning team demonstrated that good tactics and stable performance in all categories can lead to best overall scores in the end,” he added.