Cyber-attack - It's not a matter of how but when?

Yet again this week we have seen a major attack affecting some big names such as Twitter, Netflix and Reddit. More than half the internet was affected through a major DNS provider who were the main target of the attack  

Is your business prepared for scenarios such as ransom-ware, denial of service through third party services as in this case?  

Aside of the technical issues have you got a communications plan in place to advise the necessary person i.e. customers; board members regulating bodies; the public etc.....