The DPRK may have some hidden assets as reported here:
A recent report by the U.S. Congress’ research unit Congressional Research Service (CRS) has raised questions about North Korea's ability to transform cargo ships into missile launch pads. The CRS report said that North Korea has developed a submarine- or ship-mounted ballistic missile system with a range of at least 2,500 kilometers. The North has also transformed ordinary cargo ships to launch the missiles, the report said.More here on submrine launch threat.
South Korean military authorities and experts said Wednesday that while the deployment of a submarine-carried missile is unlikely, but it would be possible for Pyongyang to use a cargo ship as a launch pad. North Korea’s new ballistic missiles with a range of 2,500km to 4,000km are based on the decommissioned Soviet R-27 sub-launched missile.
Missiles can be carried in a launch pad that looks like an ordinary container and be fired by simply raising the container upright, experts say. A cargo ship would be excellent way to conceal a missile as the enemy would likely ignore it as a simple commercial vessel. Intelligence authorities note that the new North Korean 12-meter ballistic missiles would fit inside a standard container. The CRS report also said that using a commercial cargo ship would be the easiest way for North Korea to carry missiles.
The CRS report may be found here in an html version. It is also available as a pdf.
See my earleir post on the subject of merchant ships carrying missiles here. See also MissileThreat.com, inclduing its movie of a merchant missile attack on Hollywood here.
Drawing of missiles in containers is from The Chosun Ilbo article. Scud TEL on a ship is my own creation.