Cyber attack had been reported yesterday by the South Korean media channels that North Korea tried to attack the GPS signals of South Korean line communication across borders. LORAN system equipped by the South to counter-cyber attack war. The Minister of Communication and Science of South said that no any damage report from Land, nor Navy or Air Space due to the impact of North attack. GPS signal attack aims to confuse/miss calculation of GPS satellite to their clients at Air, Marine and Land bases system: The satellite will report location of any either fixed or moving target by calculation its " distance" and informing of " timing reflex" back to the station. It means if the time sending signal go and back within 0.5 second for 20 km distance BUT the North Korea confuse /delay the time sending to 0.9 second, thus the satellite will say that distance is 40km !! this is a disaster for missile attack, or wrong commercial flight information.