On 20 March 2013, three South Korean television stations and a bank suffered from frozen computer terminals in a suspected act of cyberwarfare. ATMs and mobile payments were also affected. The South Korean communications watchdog raised their alert level on cyber-attacks to three on a scale of five. North Korea has been blamed for similar attacks in 2009 and 2011 and was suspected of launching this attack as well. South Korean officials linked the incident to a Chinese IP address, which increased suspicion of North Korea as "[i]ntelligence experts believe that North Korea routinely uses Chinese computer addresses to hide its cyber-attacks."
Malware related to the attack is called "DarkSeoul" in the computer world and was first identified in 2012. The Financial Services Commission of South Korea said that Shinhan Bank reported that its Internet banking servers had been temporarily blocked and that Jeju Bank and NongHyup reported that operations at some of their branches had been paralyzed after computers were infected with viruses and their files erased. Woori Bank reported a hacking attack, but said it had suffered no damage. Computer shutdowns also hit companies including the Korean Broadcasting System, Munhwa Broadcasting Corporation, and YTN.
The South Korean government asserted a Pyongyang link in the March cyber attacks, which has been denied by Pyongyang. A 50-year-old South Korean man identified as Mr. Kim is suspected to be involved in the attack.