Source of leaks (4)
I believe the answer is:
mole
(Other definitions for mole that I've seen before include "Small spot - small mammal" , "digger" , "Naevus - burrowing mammal - spy" , "Tunneller" , "Agent; breakwater" .)
I believe the answer is:
mole
(Other definitions for mole that I've seen before include "Small spot - small mammal" , "digger" , "Naevus - burrowing mammal - spy" , "Tunneller" , "Agent; breakwater" .)