Recent attacks in Brussels by terrorists and their connection with a plot to attack a Belgian nuclear power plant raise the question of whether nuclear material could ever be stolen to create a dirty bomb.

As many as 80,000 residents in western Ukraine lost power for six hours on Dec. 23. Cybersecurity firms SANS ICS and iSight Partners have attributed the blackout to Russian hacking group Sandworm and its malicious software,BlackEnergy 3.