Korean banks' peripheral systems leak data, regulator orders industry-wide IT check

Several major South Korean banks have reported customer data leaks from peripheral business systems, and the Financial Services Commission has launched an IT inspection across the entire financial industry.

Shinhan Bank's loan-agent inquiry system was attacked for three consecutive days from September 28, with data on 25,729 customers possibly exposed. KB Kookmin Bank said its staff mobile support system lost data on 119 customers, Hana Bank's sales support system involved 89, and BNK Busan Bank found on October 1 that personal data of 11 outsourced developers had leaked. None of the systems were core banking systems, but all had externally facing entry points.

FSC Secretary-General Shin Jin-chang called on banks to strengthen vulnerability checks on externally exposed systems, tighten authentication and access control, and share threat intelligence for a joint response. Some in Korea's cybersecurity community suspect attackers may have used AI agents to automate the attacks; the attacker's identity and methods remain unconfirmed.