Inpung sul is brandy. It’s made from grapes. It says so right on the bottle. 인풍술 Inpungsul is 강계포도술공장 which is Kanggye Grape Liquor Factory.
I’m not certain, but it sounds like Paekrosul.
According to the description on lonely planet forums.
Paekrosul:
A "well-known liquor," this is a Kanggye specialty from the
D.P.R.K. (aka North Korea). Shoddy packaging, with a bottle full of
defects (at least no holes beyond the necessary one) and a cap that
guarantees it will leak in your luggage, hides a truly impressive
liquor. A very attractive aroma, with a flavour to match, and a very
nice lingering aftertaste. This is stunningly good. As an added bonus,
if you drink it, you get to live for a hundred years (thus the name,
which means "hundred-years liquor"). 40% alcohol.
Also a Google image search for Paekrosul returns lots of bottles with the same logo printed on the label.
By the looks of things and the comments posted on the photo below it is a North Korean Whiskey.
https://www.flickr.com/photos/jeremyfox/7070619751/
This is confirmed by another blogger, which apparently is available from a shop at the DMZ.
Additional Info
Found another blog with the trip to DMZ with a picture of the alcohol from North Korea but the bottle for Brandy is different from the one listed in the original, but wording on the label is similar.
Credit:stackoverflow.com‘