A breach of South Korea’s military database in which suspected North Korean hackers pilfered defense secrets originated in compromised third-party cybersecurity software and was made possible by an unintended connection to the internet.
SEOUL—A breach of South Korea’s military database by suspected North Korean hackers originated in compromised third-party cybersecurity software and was made possible by an unintended connection to the internet, according to people familiar with the attack.
The cyberassault in September last year, in which South Korean and U.
