On Thursday, the South Korean communications watchdog, which analyzed the source of the code that caused massive computer outages at some of the country's banks and broadcasters, said part of the virus came from a Chinese IP address. The outages at TV broadcasters KBS, MBC and YTN and at three banks affected operations and financial services.
The Korea Communications Commission, noting the malicious code, and not cyberattack, was responsible for Wednesday's outages, said a Chinese IP address had accessed the update management server of NongHyup, one of the affected banks, to generate malicious files, Yonhap News reported.
The malicious code slowed or paralyzed the systems. However, the disruption did not affect South Korean government institutions.
The KCC said it believes the six affected institutions were attacked by a single entity but did not elaborate, the report said.
"The Chinese IP may trigger various assumptions. At the current stage, we are open to all possibilities and are doing our best to track down the hacker," said KCC official Park Jae-moon.
The latest incident comes as tensions mount on the Korean Peninsula following last month's nuclear test by North Korea and its growing provocative and threatening statements since then.
The South has accused North Korea of carrying out cyberattacks on South Korean websites in recent years but the Communist country has denied it.
To prevent a repeat of Wednesday's disruptions, the South Korean government has distributed antivirus programs that can be downloaded from the Korea Internet Security Agency website, the report said.