South Korean officials said that 30 million customers of the Nonghyup agricultural bank were unable to use ATMs or online services for several days and that key data were destroyed, making it the most serious of a series of incidents in recent months. But even more troubling was the prospect that a belligerent neighbor had acquired the tools to disrupt one of the world’s most heavily wired nations — and that even more damaging attacks could be in store.
Conclusively identifying who ordered a cyberattack is notoriously difficult. But Western analysts who studied the incident agreed that the aggressor was probably North Korea and described it as the first publicly reported case of computer sabotage by one nation against a financial institution in another country.
Read more: Suspected North Korean cyberattack on a bank raises fears for S. Korea, allies