You are correct. However, Israeli submarines can reach North Korea and they are believed to be able to carry nuclear cruise missiles, so yes, they have a deterrent even against North Korea.
Fatboy gonna set off an ICBM... North Korea Preparing to Test Intercontinental Ballistic Missile, Kim Says JAN. 1, 2017 — North Korea’s leader, Kim Jong-un, said on Sunday that his country was making final preparations to conduct its first test of an intercontinental ballistic missile — a bold statement less than a month before the inauguration of President-elect Donald J. Trump.
I don't know about this. I don't like the idea of that wackjob regime with ICMBs in addition to nuclear warheads.