Marcus Murray has spent more than two decades probing the weak points of financial institutions. As the founder of Truesec, one of Sweden¡¯s biggest cybersecurity firms, he has helped banks across Northern Europe protect themselves against intruders.

Increasingly, though, clients are concerned about a different type of threat ¡ª state actors not trying to steal or extort money, but simply to cause chaos by shutting down banking systems or eroding trust in their operations.