This is a small excerpt from NY Times today.
"He added that ?we believe Pyongyang has already taken initial steps? toward fielding what he called a ?road-mobile intercontinental ballistic missile.? He appeared to be referring to the KN-08, provided to North Korea by a Russian company and based on the design of a Russian submarine-launched nuclear missile."
This is stripped from wiki on their sub capabilities.
"The Korean People's Navy is not known to have any ballistic missile submarines in its inventory, but has acquired 2 Foxtrot class and 10 Golf-II class submarines for scrapping in 1993. The latter are capable of firing three SLBM. It is possible that North Korea has refurbished some of those with the help of more than 20 Russian experts or upgraded them to accommodate the larger Musudan-1. Another option is that their launch tubes have been studied, and either externally fitted to Romeo/Whiskey-class submarines, or simply deployed on a cargo ship. In both cases, the DPRK has vessels capable of striking American bases in Japan, Guam, Hawaii, or even targets on the west coast of the United States."
All that said it really comes down to a waiting game. Keep in mind two of their submarines went missing over a week ago. I can't find any sources on what class the subs were or capabilities, but I believe it's safe to say Russia and China are behind the technology. Not that we of all nations should judge. We've been giving our enemies technology and selling weapons for decades.
