A massive cyber attack on major broadcasters and banks in South Korea on Wednesday originated from China, authorities here have discovered.

Analyzing the computer network at agricultural lender Nonghyup, one of the banks affected by the attack, revealed that a Chinese IP address was used to access the server to generate a malicious code, the Korea Communications Commission said.

But a team of investigators composed from the government, military and private sector are continuing to track the source of the cyber attack and believe it will take at least a month before they can produce any results.

A Cheong Wa Dae official on Thursday said, "We have a strong suspicion that North Korea is behind the latest cyber attacks."

Meanwhile, Kim Jang-soo, the nominee for presidential security adviser, was cited by a Cheong Wa Dae spokesperson as saying on Thursday the government is ruling nothing out, neither an official attack from North Korea nor an effort by a group of private hackers.