The computer networks of major broadcasters KBS, MBC and YTN, as well as banks including Shinhan, Nonghyup and Jeju Bank became paralyzed starting at 2:10 p.m. on Wednesday. The broadcasters had no problems airing programs, but their internal network shut down, preventing reporters from filing stories.
Operations at the affected banks came to a grinding halt, with customers unable to conduct any financial transactions almost two hours. Hackers cloak their origins and it can take more than six months to track their source.
In 2009, 435 computer network servers in 61 countries that were infected with a malicious code launched a so-called distributed denial-of-service attack against 35 major websites in the U.S. and South Korea by causing a large number of zombie computers to access a particular website at the same time to paralyze it.
In 2011, 747 servers in 70 countries caused several South Korean websites to shut down by the same method, while a hacking program that was planted inside a network operator's laptop accidentally infected Nonghyup bank's computer network and paralyzed it.
Officials here suspect North Korea was behind both incidents, but a strong denial from Pyongyang has made it difficult to clearly identify the source, and thus no effective punitive measures were taken.
Pyongyang only recently threatened to scrap a ceasefire agreement that halted the 1950-53 Korean War and vowed to attack the South "in a formidable way" for holding annual joint military drills with the U.S. That suggests the computer networks that serve South Korea's key state agencies and nuclear power plants could also come under attack.
North Korea has been training cyber warfare specialists since the 1990s after it could not find the money to bolster its conventional military hardware. The North apparently has 30,000 cyber warfare specialists.
South Korea's major government, military and business organizations all rely on a world-leading IT network to operate, but they are also highly exposed to cyber attacks. Urgent steps are needed to bolster cyber defenses and to ensure that computer networks can be put back into operation quickly if they are hacked.
The U.S. recently announced it would create 13 military units by 2015 to deal with cyber attacks. Seoul, too, needs to come up with measures against cyber terror and cooperate as much as possible with other advanced countries.