Their MX record (the servers that people will contact to send them email) point just to straight up O365/EOP, which is dogshit for protection. Their other DNS records for email authentication are also quite telling. The one which says which IPs are allowed to send email on their behalf, is fuckoed. The one that is designed to gather information about who is sending on their behalf and (the way it is currently configured) send unauthorised email to the junk/spam folder, shows that they are trying to implement domain spoofing protection by themselves (which always ends in tears). And anyway, send that stuff to junk is pointless, as users can still access it.
Tl;dr - this could very easily have been an email compromise. But of course this is conjecture.
Their MX record (the servers that people will contact to send them email) point just to straight up O365/EOP, which is dogshit for protection. Their other DNS records for email authentication are also quite telling. The one which says which IPs are allowed to send email on their behalf, is fuckoed. The one that is designed to gather information about who is sending on their behalf and (the way it is currently configured) send unauthorised email to the junk/spam folder, shows that they are trying to implement domain spoofing protection by themselves (which always ends in tears). And anyway, send that stuff to junk is pointless, as users can still access it.
Tl;dr - this could very easily have been an email compromise. But of course this is conjecture.