It also depends on the circumstances of the application process. There are a lot of thieves taking advantage of a lot of desperate people right now. If someone responds to a "do you want a job" email (or a dodgy web site, etc.) with an AT&T logo pasted into it, and the next question is "what's your SSN?", any sane person would recognize it as a probable scam. If you think that's ridiculously obvious, go check out how much the Nigerian 419'ers are still making.
When I was looking for the AT&T Employment link this morning, I found a message board complaining about fake "recruiters", and AT&T was one of them. Along with harvesting personal info, some of them are charging application fees. I hope there's a special place in Hell.
Anyway, OP, from your last post it sounds like a legitimate lead, so good luck!