SEOUL, South Korea — The North Korean leader Kim Jong-il has found a novel way of raising badly needed cash, according to the South Korean authorities: unleashing young hackers on South Korea’s immensely popular online gaming sites to find ways to rack up points convertible to cash.

Despite its decrepit economy, North Korea is believed to train an army of computer programmers and hackers. The police in Seoul said Thursday that four South Koreans and a Korean-Chinese had been arrested on charges of drawing on that army to organize a hacking squad of 30 young video gaming experts.

Working from Northern China, the police said, the squad created software that breached the servers for such popular South Korean online gaming sites as “Lineage” and “Dungeon and Fighter.” The breach allowed round-the-clock play by “factories” of dozens of unmanned computers.

Their accumulated gaming points were exchanged for cash at Web sites where human players are focused on acquiring enhancements for their online personas, or avatars. The gaming software was also sold, the police said; such factories, while illegal, are common in South Korea and China.