SEOUL -- Momoland is the new sensation in the world of Korean popular music, the $5-billion-a-year genre known as "K-pop." Momoland's latest song, "Boom Boom," is a hit with their legions of fans.

It's also an unlikely weapon against North Korea, where K-pop is reportedly banned. The South Korean military blasts music across the border to let North Koreans know what they're missing.

K-pop group Momoland is a hit in South Korea CBS News

South Korean pop culture is a big export in Asia, and is even making inroads in the West. There's also "K-drama," which are blockbuster South Korean soap operas. They're officially prohibited in North Korea, as is the internet. Instead there's a diet of government propaganda and Stalinist entertainment. But some North Koreans manage to get their hands on black-market copies of South Korean soap operas.

For Kim Hak-Min, a North Korean defector turned businessman, they were proof the regime was lying to him. His favorite was "Lovers in Paris."

"It was fantastic in my life," he said.

Flash drives containing soap operas are put in bottles with hopes they'll float to North Korea CBS News

Hoping other North Koreans will see the light, one aid group called No Chain for North Korea, puts flash drives containing soap operas and movies inside bottles of much needed rice, and floats them towards the North.

This frozen conflict is being fought with a very unusual arsenal.