trending hack sending emails about a support ticket

I've seen a few hundred of these emails in the past couple days coming in from multiple different companies.

I'm looking for more info.

at least one said it was zendesk, most did not say any software.

the tickets are being sent with CC addresses that contain large email lists. often others on the CC who don't know what's happening will reply "stop emailing me".

so far I've seen this coming in to multiple addresses and none of the sending companies are familiar either.

sounds familiar to anyone? any info on this? it's there a name i can lookup to find more info? i want to know what services this effects so i can properly protect my stuff and my work stuff.