NEW : China says hackers often use IP addresses from other countries . The three broadcasters -- KBS , MBC and YTN -- reported varying levels of trouble containing the virus . North Korea has staged similar attacks in the past , expert says . Previous attacks linked to the North have been traced to Chinese addresses . Comment:
NEW : China says hackers often use IP addresses from other countries . North Korea has staged similar attacks in the past , expert says . Previous attacks linked to the North have been traced to Chinese addresses . Comment: