If you're a Kiwibank customer, you might have been finding it a bit tricky to do your online banking since Saturday. MetService and Kiwibank have both been battling cyberattacks in the past week. The're among many organsations to be hit with a distributed denial of service (DDoS) attack. Those include ANZ, New Zealand Post and the Ministry for Primary Industries - and the Waikato DHB was also hit by a cyber attack. The chief executive of the Telecommunications Forum, Paul Brislen, joins Bryan Crump to understand why it happens and who's to blame.