OK Savings Bank Confirms Personal Data Leak Affecting 250 Customers; Annual Incomes and Account Numbers Among Data Exposed

[Financial News] OK Savings Bank has confirmed that personal information belonging to 250 customers was leaked in a hacking attack. The scale of the breach was larger than the 183 customers initially estimated. The leaked information included sensitive data such as account numbers, annual incomes and loan amounts, in addition to names and contact details.
On the 15th, OK Savings Bank said that two external security monitoring firms investigated an incident involving abnormal access to the loan application webpage on its website and confirmed that personal information belonging to 250 customers had been leaked.
The leaked information consisted of loan application data, including names, dates of birth, mobile phone numbers, account numbers, addresses, email addresses, workplace names, business registration numbers, annual incomes and loan amounts.
The hacking attack took place from 8:44 p.m. on the 11th until 2:14 a.m. the following day, lasting about five hours and 30 minutes. OK Savings Bank became aware of signs of abnormal access at 10 a.m. on the 12th, about seven hours and 46 minutes after the attack ended.
At 11:35 a.m. that day, OK Savings Bank urgently deployed authorization verification logic and blocked suspected hacking IP addresses and access routes. Then, at 7:30 p.m., it brought in two external security monitoring firms and began a detailed investigation into the security breach.
At 8:40 a.m. the following day, the 13th, it first reported the possibility of a customer data leak to the Financial Supervisory Service. At the time, OK Savings Bank said that the personal information of 183 customers might have been leaked, but further investigation ultimately confirmed that the number was 250, an increase of 67.
After finally confirming the data leak at 8 a.m. that day, OK Savings Bank reported it to the relevant authorities at 9 a.m. Starting at 9:10 a.m., it began notifying each customer whose information had been confirmed as leaked by text message and email.
The bank is also advising customers not to click on internet links from unclear sources to prevent further harm resulting from the data leak, and is recommending that they use a security-blocking service. It is also operating a dedicated hotline for reporting incidents and seeking advice.
The bank has blocked the suspected hacking IP addresses and access routes, and completed urgent security checks of its systems as a whole and measures to strengthen monitoring. So far, no further signs of abnormal activity or suspicious circumstances have been identified.
An OK Savings Bank representative said, “We sincerely apologize for causing concern to all our customers who trust us and use our services,” adding, “We will use this incident as an opportunity to conduct a comprehensive review of our personal information protection framework and security systems, and do everything we can to strengthen our security systems to prevent a recurrence.”

[email protected] Seo Ji-yoon Reporter