Looks like it took them about six days to figure out why their customers were getting spammed. It'd be helpful if they could outline what the "non-core system

Looks like it took them about six days to figure out why their customers were getting spammed. It'd be helpful if they could outline what the "non-core system that allows us to communicate service-related announcements to users via email" actually was. Was this a Mailchimp account that got hacked into or did they have something they managed?