KB Kookmin Bank Data Breach Expands to 2,210 People

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KB Kookmin Bank has increased the number of individuals whose personal information was leaked in a hacking incident from an initial 119 to 2,210 people.

Following a detailed analysis conducted on October 26 with financial supervisory authorities and related agencies, the bank identified an additional 2,091 victims, consisting of 1,631 customers and 460 employees. This increase is approximately 18.6 times the original figure. The bank clarified that this expansion did not result from a new hacking attack, but from the re-verification of data and business processing within the system where the original breach occurred.

The breach originated in a mobile business support system used by bank employees, which the bank stated is separate from customer financial transaction systems such as internet or mobile banking. The bank first recognized the external breach in this system on September 30 and disclosed the leak on October 2.

For customers, the leaked data includes names, dates of birth, addresses, phone numbers, encrypted resident registration numbers, occupation information, annual income, account numbers, deposit balances, loan transaction history, credit ratings, and credit card delinquency information. The specific types of information leaked vary by customer. For current and former employees, the leaked data includes names, employee numbers, mobile phone numbers, email addresses, department affiliations, and appointment or retirement dates.

The Financial Supervisory Service reportedly identified the additional leaks during a regular inspection of KB Kookmin Bank. Consequently, the adequacy of the initial investigation and the estimation of the leak scale are expected to be reviewed. KB Kookmin Bank is currently notifying affected individuals and operating a representative call center and a dedicated counseling center. The bank has previously stated its policy to provide full compensation if customer damage occurs.