In my organization we sync our Office 365 with active directory and lately we have been receiving tons of spam (some containing malware) sent to our All Staff groups and other groups. I saw in Office 365 you can block distribution groups from receiving mail from outside your organization but since we sync our users and groups with Active Directory I cannot enable that. I was thinking there had to be some attribute I could edit to make that happen on the Active Directory object but I have no idea which Attribute would control that.
If Anyone happens to know Active Directory attributes really well and can help me find the attribute that I can change to allow our email distribution groups to ONLY receive mail from within our organization that would be Awesome.