Exact figures on how much it is costing British firms vary but recent research from the UK government found that eight out of ten large companies had suffered a breach and most were seeing attacks on at least once a month.
But nowadays it is increasingly attracting professional criminals.
They can make good money from cybercrime and the risk of getting caught is low.
Even if they do get caught the punishments are far less arduous than if you get caught robbing an actual bank or dealing drugs.
The huge growth of Bitcoin and other alternative currencies have also made it much easier for the crooks to get paid.
The traditional way of protecting a business against cyber-attack was to protect the perimeter.