Sorry for the confusion!
What I meant was that right after security you are at B17 (at least from where I entered the security line after taking the train from the international arrivals terminal). I'm sure that ORD probably has different security check locations that deposit you somewhere.
I check in at ORD only about once a year and only after an international arrival.
From B17 it was only a 5 min walk to B1 or to the other end.
Bob