South Korean investigators say they were mistaken when they said a cyber attack that paralyzed tens of thousands of computers at six companies this week originated in China.
Seoul's Korea Communications Commission said Friday that an Internet Protocol address linked to Wednesday's attack actually belongs to a computer at one of the South Korean companies that were hit.
The KCC said an analysis of malware and servers indicates the attack was probably orchestrated from abroad, but they did not elaborate.
However, the Yonhap news agency quoted a high-ranking official as saying Seoul bears a "strong suspicion" that North Korea conducted the attack.
The attack paralyzed computers at broadcasters YTN, MBC and KBS, as well as two commercial banks - Shinhan Bank and Nonghyup Bank.
South Korea's military raised its alert level after the attack, though the military was not targeted.
North Korea is believed to have an elite cyber warfare unit that was suspected of being behind computer attacks on South Korean government agencies and financial institutions in 2009 and 2011.