How many Daishin Securities customers had personal or credit information leaked, and how did the breach happen?

Daishin Securities said information belonging to 38,490 customers was leaked. It detected signs of unauthorized access on Oct. 17 to a server linked to online securities account openings for discretionary investment services.

Which parts of Korea’s financial sector have been affected by the recent cyberattacks, and which major segment has not been confirmed affected?

The attacks have spread from banks and savings banks to other major financial-sector segments, including cryptocurrency exchanges, asset managers and securities firms. Damage has been confirmed across all major segments except credit card companies.

BreakingBithumb, Mirae Asset, Daishin join growing list of cyberattack victims

Q: What information was exposed in the Bithumb cyberattack, and what is the company still investigating?

Bithumb said personal information was leaked after unauthorized access to its internal mobile groupware system. It is examining the scope of the breach, including whether customer information was compromised.

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Summary

Daishin Securities, Bithumb and Mirae Asset Global Investments reported cyberattacks in Korea on Wednesday. Daishin said information belonging to 38,490 customers had been leaked after unauthorized access to a server linked to online account openings. Bithumb found personal information had been exposed through its internal mobile groupware system and is assessing the breach. The incidents extend a wave of attacks across the financial sector, with credit card companies the only major segment not yet confirmed affected.

Key Facts

Daishin Securities detected signs of unauthorized hacker access on Oct. 17 to a server connected to online securities account openings for discretionary investment services.
Bithumb discovered the leak on Tuesday and is investigating whether customer information was compromised.
Financial authorities are investigating the extent and circumstances of the breach at Mirae Asset Global Investments.
Mirae Asset Life Insurance detected unusual system activity on Sunday and launched an emergency response after identifying a cyber intrusion.
The recent wave began with a reported breach at Shinhan Bank on Sept. 30 and spread from banks and savings banks to other major financial-sector segments.

By Jun Ji-hye

Published Oct 28, 2026 10:17 am KST

A man sits at Bithumb Lounge in Seocho District, Seoul, Monday. / Yonhap

Cryptocurrency exchange Bithumb, asset manager Mirae Asset Global Investments and Daishin Securities have become the latest victims of cyberattacks sweeping Korea’s financial sector, industry officials and financial authorities said Wednesday.

Daishin Securities said in a press release earlier in the day that personal and credit information belonging to 38,490 customers had been leaked. The brokerage said it detected signs of unauthorized access by a hacker on Oct. 17 to a server linked to online securities account openings for discretionary investment services.

Bithumb discovered Tuesday that personal information had been leaked following unauthorized access to its internal mobile groupware system. It is examining the scope of the breach, including whether customer information was compromised.

A hacking incident was also reported at Mirae Asset Global Investments, prompting financial authorities to investigate the extent of the damage and the circumstances of the breach.

The latest incidents came after Mirae Asset Life Insurance detected unusual activity in some of its systems Sunday and launched an emergency response after identifying a cyber intrusion. It was the first insurer confirmed to have been affected in the recent wave of attacks.

Since a breach at Shinhan Bank was reported on Sept. 30, cyberattacks have spread from banks and savings banks to other major segments of the financial sector.

With damage now confirmed across all major segments except credit card companies, the suspected artificial intelligence (AI)-assisted attacks are raising concerns about the industry's ability to defend against cyber threats.

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