From what I have seen on Google Earth, they are in shelters dug in. Have to be earth penetrating bombs, BEFORE they get a chance to launch. Ships cannot evade in that narrow channel, so get them early. Luckily, I suspect we have drones 24/7 watching the area and would see if the muzz start pulling out missiles getting ready to fire. Radar emissions might tip off that they are setting up targeting solutions.
Problem would be if any can be fired from concealment or sheltered. Dunno about that sort of stuff, but the old Silkworm had to be outside.