OK Savings Bank hit by second hack, leaking data of 268 more customers

OK Savings Bank has confirmed a second hacking incident, exposing the personal data of 268 customers — a fresh blow coming just days after a breach on Monday compromised information belonging to 250 customers through its loan application webpage. The back-to-back incidents have raised alarm over security management across the financial sector, as cyberattacks continue to strike commercial banks, savings banks, capital companies and electronic financial firms.

The lender said it discovered the additional breach during a full system inspection conducted through Thursday following the first incident. The newly compromised page was linked to a mobile deposit notification service, and the leaked data included customer names, account numbers, product names, account balances, interest rates and the dates of their most recent transactions.

The company said the IP address used in the second attack differed from the suspicious IPs the Korea Financial Security Institute had shared in advance. OK Savings Bank reported the breach to the Financial Supervisory Service and individually notified affected customers by text message and email.

The bank said it has completed follow-up measures, including blocking the suspicious IP address, patching its account-inquiry defense logic and applying an emergency anomaly detection and blocking solution. It added that no new unauthorized access has been detected.

Earlier, OK Savings Bank announced Monday that a hack targeting its loan application webpage had exposed the names, dates of birth, addresses, annual incomes and loan amounts of 250 customers.

"We discovered the additional data leak while conducting a comprehensive review of our systems," an OK Savings Bank official said. "We sincerely apologize again for causing concern to our customers."

Hacking incidents have been spreading across the financial industry. The Financial Services Commission released findings Wednesday confirming breaches at 16 financial institutions — including Shinhan, KB Kookmin, Hana and BNK Busan Bank, as well as savings banks, mutual finance firms, credit finance companies, electronic financial firms, online peer-to-peer lenders and virtual asset operators. The number of personal records confirmed as leaked up to that point stood at approximately 100,000.

An emergency security inspection of 555 financial firms conducted by regulators found that 130, or 23.4 percent, reported deficiencies in their security management. Key problems included failure to apply the latest security patches, poor management of legacy systems no longer receiving technical support, and the absence of round-the-clock security monitoring. A number of deficiencies were also found at some electronic financial firms and online peer-to-peer lenders, which tend to have relatively weaker security capabilities.

Authorities are investigating the attack vectors, methods and possible links among the recent incidents. They are also examining whether AI was used in the attacks, while directing financial firms to review security vulnerabilities in their externally exposed IT systems and services.