Would assume someone would notice all the data that is being transferred. And if this turns out to be a sophisticated attack then who’s to say they didn’t back

Would assume someone would notice all the data that is being transferred. And if this turns out to be a sophisticated attack then who’s to say they didn’t backdoor a bunch of systems? I heard a talk from a big Norwegian company that got attacked. Every single server, every single switch, every single laptop, all had to be reformatted and reinstalled. I assume that AT&T would have to end up doing the same.