I found a large amount of mold on the drywall that is directly behind a tub/shower in a bathroom. I removed the infected drywall to find the leak and it appears that the tub spout was loose, probably due to poor caulking/movement from pulling the diverter tab to divert water to shower/everyday use. It appears the water was leaking through the shower to the wall area where the pipes and drywall are. I believe the fix is to replace the plastic piping from the diverter to a 90 degree elbow to the tub spout with all copper and secure the 90 elbow to a 2x4 between the studs to make sure the piping to the tub spout does not move over time and cause additional leaks. I have limited experience and am trying to troubleshoot this and was curious if anyone had any additional input that could help me figure this out. Thank you and my apologies for misuse of terminology.