The Korea Internet Security Center run by the Korea Internet and Security Agency monitors cyber attacks and hacking incidents targeting domestic websites around the clock.
Friday's GPS jamming and cyber attacks, which are suspected to be the work of North Korea, have led to a flood of speculation among experts about possible future provocations by the North. Some now fear that it could resort simultaneous cyber attacks against South Korean power, traffic, communication, military and other state infrastructure.
The government believes North Korea was behind a so-called distributed denial-of-service attack and jammed GPS signals in some parts of South Korea. Some fear the attacks could even be the first stage of an all-out cyber war. How ready is the South for the threat?
Nuclear power accounts for 35.7 percent of the South's electricity production, and an attack on the computerized systems operating plants could plunge the country into chaos. But they are virtually impossible to hack into since their operating systems are isolated from external Internet networks. But viruses can infiltrate them through USB memory devices, CD ROMs or external hard drives.
Fortunately each nuclear power plant has a separate system, making it impossible to damage all of them at a single attack.
The KTX high-speed rail network is controlled by a single command center. A failure in its operating system would cause havoc on the trains because they would no longer be able to control their speed, direction and signals. In the worst-case scenario, they could collide, which could result in hundreds of fatalities.
North Korea has apparently collected a lot of information on South Korea's rail and subway operating systems. The North could use an agent to insert a virus into the KORAIL system via a USB memory stick or external hard drive to paralyze it. That is why KORAIL employees are strictly prohibited from using USB memory devices.
If air traffic systems at airports are attacked, passenger planes could end up crashing into runways or into each other in mid air.
But an airline industry insider said air traffic control systems automatically stop operating at the smallest sign of trouble, and that makes them relatively safe from cyber attacks.
"Backbone networks like air traffic control systems cannot be attacked via the Internet, as in the case of DDos attacks," said Cho Shin, a director at computer safety firm Ahn Lab. "But it is possible if done with the help of an insider after gathering the right information."
Another possibility is a stock market crash triggered by a cyber attack.
Trading systems could become immobilized by an explosive rise in the number of transactions, or bogus deals could be made. One North Korean defector who used to work in a cyber warfare unit in the North said, "We focused our research on the servers at South Korean financial institutions. North Korea is capable of hacking or attacking them."
Gas transmission and distribution pipelines and sewers in the metropolitan areas are exposed to cyber threats. Raising the pressure on a gas pipeline would heighten the risk of explosion or leaks. The gas supply comes from private suppliers that each have their separate maintenance and inspection procedures and guidelines, which raises concerns about how secure they are.
The government is trying to come up with measures including providing security software.