The danger of "sleeper" Hezbollah moles is certainly very real. It is their easiest way to stike Israel and smuggling explosives and weapons is quite feasible, if done over a long time. And there has been a long time. Defence involves intelligence work,instead of military action Israeli intellingence has been known to be up to the task. Let us hope it finds them in time.
U.S. defense contractor accused of copying secret military documents (Reuters)
from the article: Why did Israel attack Syria now, and why did the Syrians admit it?