AIRPORT software is being held for ransom by criminals as travel chaos persists following a massive cyber attack. The EU's cyber security agency says that malicious software is being used to hamper check-in services at major terminals. It is still not known for sure who is behind the crippling cyber attack that wreaked havoc across the continent. Security specialist Will Geddes also told The Sun that it's "very likely Russia is behind the devastating cyber attack". 5 Berlin Airport is among those affected by the attack Credit: Alamy