No one will take a chance and attack them, its not worth it. They will get one and it will be a situation of Mutual Assured Destruction (MAD). Both Israel and Iran know that a lunch will automatically lead to a second strike. Even Ahmadinejad (or at least Khomeini) aren't crazy enough to lead to their own country's destruction or millions of deaths.
Turkish warplanes attack PKK targets after soldier killed in attack (Reuters)
from the article: Mossad chief: Nuclear Iran not necessarily existential threat to Israel