Cyberattack wave widens across Korean financial sector

Cyberattacks have hit more South Korean financial firms, with brokerage Daishin Securities reporting a data breach affecting more than 38,000 customers, while cryptocurrency exchange Bithumb and asset manager Mirae Asset Global Investments also confirmed security intrusions.

The incidents extend a weeks-long wave of cyberattacks across the financial industry, raising concerns over security vulnerabilities and prompting the country's financial watchdog to call for stronger defenses.

Daishin Securities said Wednesday that personal and financial information belonging to 38,490 customers was exposed after hackers gained unauthorized access to a server linked to its online account-opening service.

The brokerage said it detected suspicious activity on Oct. 17 and subsequently examined more than 60,000 requests disguised as legitimate service traffic over a 10-day period.

The leaked information included customer names, email addresses, physical addresses, bank names and account numbers, as well as encrypted phone numbers and account details.

Daishin said it had found no evidence of unauthorized access to its core trading systems or further harm to customers so far. The company plans to notify affected customers individually and compensate those who suffer losses under applicable laws.

"We acknowledge the seriousness of this breach and sincerely apologize to our customers," Daishin CEO Jin Seung-wook said. "We will take full responsibility for implementing measures to protect customers and prevent a recurrence."

Bithumb also reported a data breach after detecting unauthorized access Tuesday to its internal mobile groupware system, operated through third-party platform Daou Office.

The exchange said customer assets were unaffected because the compromised system is not used by customers and is physically separated from its trading network. It reported the breach to the Korea Internet and Security Agency and the Personal Information Protection Commission and is investigating whether any customer data was exposed.

Mirae Asset Global Investments separately confirmed unauthorized access to some of its web systems. The asset manager said it blocked the access routes and launched an emergency response after discovering that information from internal business systems had been exposed.

Preliminary findings showed no evidence that sensitive personal information, credit data or investor information was compromised, the company said. It has reported the incident to financial regulators and is working with external cybersecurity experts to investigate the cause and prevent a recurrence.

Earlier in the week, affiliate Mirae Asset Life Insurance also confirmed a customer data breach, prompting an on-site inspection by the Financial Supervisory Service.

The latest cases add to a series of cyberattacks across the country's financial industry in recent weeks. Shinhan Bank, KB Kookmin Bank and Hana Bank were among lenders that reported customer data leaks earlier this month, while savings banks and other financial institutions have also been targeted.

Against this backdrop, FSS Gov. Lee Chan-jin urged financial firms to strengthen their cybersecurity defenses during a meeting with board chairs from eight banking groups Wednesday.

"Cyberattacks are becoming increasingly sophisticated, with targets expanding to noncore systems," Lee said, warning that AI could make it easier for hackers to identify vulnerabilities and launch simultaneous attacks.

He called on financial firms to proactively address security weaknesses rather than focus solely on regulatory compliance.

"IT security is essential to protecting customers' assets and information and maintaining trust in finance," Lee said, urging boards to take greater responsibility for cybersecurity.

The FSS has dispatched inspectors to Daishin Securities and is assessing the incidents at Bithumb and Mirae Asset Global Investments, alongside its ongoing investigation into the breach at Mirae Asset Life Insurance.