The Koreans had been hoping for a win in their final match on home soil before heading to Europe but lacked accuracy in attack and looked fragile with a three-man defence at the back.
Winger Visca gave the visitors a 28th-minute lead but midfielder Lee Jae-sung, rested for Monday's 2-0 win over Honduras, immediately hit back with a cool finish on the back of a rare fluent attacking move from the home side.
Visca again found space down the right of the Korean defence to put Bosnia back in front on the stroke of halftime, though, and lashed home his third in the 80th minute to silence a big crowd at Jeonju World Cup Stadium.
Korea coach Shin Tae-yong will cut three players from his squad before they head to Austria to make their final preparations for the finals, where they face Sweden, Mexico and world champions Germany in Group F.
(Reporting by Nick Mulvenney in Sydney, editing by Christian Radnedge)
