Non-freeze hose bib

I have a non-freeze hose bib on a house that the owner left a hose connected to this past winter (and it was a cold one in here in the northeast!).

It is installed thru an 8" CMU wall parged on the outside and the basement is finished on the inside (1" air space, 2x4 wood studs and 1/2" drywall). When the hose bib is turned on it provides water just fine but the CMU basement wall gets wet all around the bib. I'm talking about an apparent leak within the CMU cores of the wall. No sign of leaking inside on the drywall. When the bib is shut off the CMU and parging eventually dry out.

What happened to this bib? The washer is is the bib shot? Why does it show signs of leaking when turned on but not in the off position? Is this something that can be fixed by removing the stem from the outside or am I looking at cutting the dry and doing the fix from the inside? I'm guessing that the bib cracked between the shutoff and the outside correct?