Ask HN: Hacked Ionos Email Account

A colleague of mine has started receiving a ton of failed to deliver responses on an email he has setup with IONOS. The IPs all seem to be coming out of us-west / oregon.

The only thing we can tell is (in one instance):

- Subject: 'VoiceM_Notifications' - From: Ajdan VMail SUPP0RT - To: ...@ajdan.com.sa

I'm bit at a loss to figure out how to help them stop the email barrage from being sent out. Calling the email service resulted in them just saying that there isn't any unusual activity, which obviously isn't the case.

The emails that are being sent out are not being populated from our own contact list, and my guess is my colleague clicked on an a similar email which resulted in this activity.

Tried looking up what the recommended approach to this behavior is, but couldn't come across anything. Anyone have experience with this?