Korea hacking wave: Bithumb, Daishin, Mirae Asset breached; 38,490 hit
Crypto exchange Bithumb, brokerage Daishin Securities and Mirae Asset Global Investments have all reported cyber-attacks, with personal data of 38,490 Daishin customers exposed, and South Korea's financial watchdog has sent inspectors.
At a glance
- Daishin Securities said hackers reached a server for its online account-opening service, exposing names, emails, addresses, bank names and account numbers of 38,490 customers.
- Crypto exchange Bithumb found unauthorised access to an internal mobile groupware system on Tuesday, October 27; it says customer assets are safe and is checking whether customer data was exposed.
- Mirae Asset Global Investments detected unauthorised access to some web systems but says no investor or credit data was taken; its affiliate Mirae Asset Life Insurance reported a breach earlier in the week.
- The Financial Supervisory Service (FSS) sent inspectors to Daishin and is assessing the other cases; no link between the attacks has been established.
- Shinhan, KB Kookmin and Hana banks already reported customer data leaks this month.
Three more South Korean financial companies — cryptocurrency exchange Bithumb, brokerage Daishin Securities and asset manager Mirae Asset Global Investments — have reported cyber-attacks, widening a wave of breaches that has hit the country's banks and investment firms this month. Daishin said the personal and financial details of 38,490 customers were exposed. The Financial Supervisory Service (FSS) said on Wednesday, October 28, 2026, that it had sent inspectors to Daishin and was assessing the other incidents.
What each company reported
Daishin Securities said hackers gained access to a server linked to its non-face-to-face (online) account-opening service. Abnormal access was first detected on October 17, and the company then reviewed more than 60,000 disguised requests made over about 10 days. Exposed data includes customers' names, email addresses, home addresses, bank names and account numbers, while phone numbers were encrypted. Daishin said core trading systems were not reached and it has found no sign of secondary damage. Chief executive Jin Seung-wook apologised and pledged to take full responsibility.
Bithumb, one of South Korea's two largest crypto exchanges, said an outsider accessed an internal mobile groupware system, run on a third-party platform, on Tuesday, October 27. The company said the system is isolated from trading and is not used by customers, so customer assets are safe. It reported the breach to the Korea Internet & Security Agency (KISA) and the Personal Information Protection Commission and is checking whether any member data was exposed; so far, employee information is confirmed to have leaked.
Mirae Asset Global Investments said it found unauthorised access to some web systems, blocked the access routes and launched an emergency response. Preliminary findings show no personal, credit or investor information was compromised. Its affiliate Mirae Asset Life Insurance confirmed a customer data breach earlier in the week, and the FSS is already inspecting it on site.
| Company | Type | Detected | Data exposed | Regulator action |
|---|---|---|---|---|
| Daishin Securities | Brokerage | Oct 17 | 38,490 customers' personal and bank data | FSS on-site inspection |
| Bithumb | Crypto exchange | Oct 27 | Employee data confirmed; customer data being checked | Assessment; reported to KISA, PIPC |
| Mirae Asset Global Investments | Asset manager | This week | None found so far | Assessment |
| Mirae Asset Life Insurance | Insurer | Earlier this week | Customer data | FSS on-site inspection |
Background: a month of breaches
The new cases follow customer data leaks reported earlier in October by three of the country's biggest lenders — Shinhan Bank, KB Kookmin Bank and Hana Bank — and attacks on savings banks and other institutions. Officials say no link between the latest incidents has been established, and it is not yet known who is behind them.
Reactions
FSS Governor Lee Chan-jin met the board chairs of eight banking groups and urged them to fix security weaknesses proactively rather than treating protection as a compliance box-ticking exercise. He called on boards to take greater responsibility and warned that artificial intelligence could help attackers find weaknesses faster and launch several attacks at once.
Why it matters
South Korea has one of the world's most digital financial systems, with tens of millions of people trading shares and crypto through apps. Leaked names, addresses and account numbers are valuable for phishing and voice-phishing scams, which already cost Korean consumers heavily each year. Repeated breaches could also push regulators towards tougher penalties and mandatory security spending for financial firms.
What happens next
Daishin will notify affected customers individually and compensate any proven losses. Bithumb and Mirae Asset are continuing investigations with outside experts, and the FSS inspections could lead to sanctions if firms are found to have broken data-protection rules. Customers should be alert to calls, texts or emails that mention their personal details, and should never share passwords or one-time codes.
Questions people are asking
Was Bithumb hacked?
Yes. Bithumb confirmed that an outsider gained unauthorised access to an internal mobile business system, detected on October 27, 2026. The exchange says the system is separate from trading, customer assets are not affected, and it is checking whether any customer data leaked.
How many Daishin Securities customers were affected?
Daishin Securities said personal and financial data of 38,490 customers was exposed, including names, emails, addresses, bank names and account numbers, with phone numbers encrypted. It will notify each customer and compensate any losses.
What should affected customers in Korea do?
Watch for phishing calls, texts and emails that use your name or account details, never share passwords or one-time codes, change passwords on financial apps, and contact your firm directly through its official app or number if anything looks suspicious.
