The South Korean military raised its cyberattack readiness level Wednesday following the shutdown, the Defense Ministry said. Defense officials reported no signs of cyberattacks on its ministry’s computer network and had no immediate details about the broader shutdown. No government computers were affected, officials said. President Park Geun-hye called for quick efforts to get systems back online, according to her spokeswoman, Kim Haing. The investigation will take months, Lim said. “Hackers attack media companies usually because of a political desire to cause confusion in society,” he said. “Political attacks on South Korea come from North Koreans.” Massive shutdowns of the networks of major companies take at least one to six months of planning and coordination, said Kwon Seok-chul, chief executive officer of Seoul-based cyber security firm Cuvepia Inc.