Mirae Asset Securities hit by cyberattack, data of 39,000 exposed

Amid a string of cyberattacks targeting the financial sector, Mirae Asset Securities has disclosed a data breach affecting more than 39,000 customers and employees.

The brokerage said Saturday that its mobile web phone-authentication login service and internal groupware system, mi-global, came under external attack over two days beginning Wednesday.

The breach exposed the account numbers of about 3,800 customers. The company said no sensitive information beyond account numbers — such as account holder names — was leaked.

The scale of the employee data breach was larger. Personal information belonging to 35,255 current employees, former employees and contract workers was exposed. The leaked data included names, employee identification numbers, email addresses, mobile phone numbers and encrypted passwords.

Unique identifying information — including resident registration numbers, passport numbers, driver's license numbers and alien registration numbers — was not among the leaked data, the company said.

After detecting signs of abnormal access from external IP addresses, Mirae Asset Securities blocked the access routes and activated an emergency response system. The company also reported the incident to relevant authorities, including the Financial Services Commission, the Financial Supervisory Service and the Personal Information Protection Commission.

The company said the incident involved unauthorized external access to data, and did not result in malware infection or service disruption. No financial losses have been confirmed so far, it added. Major systems and services, including the company's website, are operating normally.

Mirae Asset Securities posted an apology signed by co-CEOs Kim Mi-seop and Heo Seon-ho. "We again sincerely apologize for failing to fulfill our responsibility to protect our customers' valuable personal and credit information," the statement read. "We are thoroughly investigating the cause of the incident and the circumstances of the leak, and are putting in place measures to prevent a recurrence."

The breach has heightened concerns about information security management across the financial sector. Observers note that the large-scale exposure of employee email addresses, mobile phone numbers and encrypted passwords raises the possibility of secondary damage such as phishing attacks or account takeovers.