So, back on topic.
As abject poverty and a high-toll famine was at it's height in North Korea, the benevolent Russia sold NK hundreds of millions of dollars worth of weaponry. The main reason NK's economic sanctions are in place.
Its not like other country's weren't selling NK weapons too though, hell only 3 or so of NK's 40 MiG-29's came from Russia, however it was admittedly very opportunistic as one of the main reasons for the famine was Russia ceasing to bankroll NK after the fall of the USSR (coincidentally also a reason NK was trying to bolster its weapons as it no longer had the USSR standing behind it).