South Korea's financial sector hit by fresh cyberattacks as AI pentest tool draws scrutiny

South Korea's financial sector has been hit by another wave of cyberattacks, TechCrunch reported on October 28, with brokerages Daishin Securities and Mirae Asset Global Investments and crypto exchange Bithumb among those affected. The incidents come roughly a month after a series of attacks on South Korean financial institutions, widening concern beyond the country's banking systems.

Daishin has confirmed a breach that exposed customer data. According to local news cited by TechCrunch, the attack exposed the personal information of 38,490 customers, including names, email addresses and mobile phone numbers. The company has notified affected customers, is cooperating with authorities and will compensate for losses as required by law.

Mirae and Bithumb reported separate cybersecurity incidents on Wednesday, though neither has confirmed that customer data was taken. TechCrunch said South Korea's Financial Services Commission, Daishin Securities, Bithumb and Mirae Asset Global Investments did not immediately respond to requests for comment.

The more telling context is the tooling. Security researchers linked the September wave of attacks on South Korea to a suspected China-based hacker who relied on an AI penetration testing tool called Artex. Officials are still investigating the root cause of the latest breaches, and investigators have not established a connection between the incidents.

Regulators are already responding. South Korea's financial regulator called for stronger cybersecurity measures following the string of attacks on financial firms and government agencies, and the country plans security checks on dozens of private-sector IT systems. A day earlier, Japan reported an incident involving GMO Internet, after a series of attacks on its own financial institutions.

Read together, the episode shows AI acting as an amplifier of attack surface: penetration testing tools are built for defenders to probe their own systems, but when misused they lower the barrier to finding exploitable holes. The targets also shifted from banks toward brokerages and crypto exchanges, where third-party integrations, customer data pools and trading systems make for concentrated value.

What to watch next is the investigative record: whether Artex is confirmed in this round, what common weaknesses the Financial Services Commission's checks turn up, and whether Korean and Japanese regulators build a joint response to a cross-border pattern. TechCrunch notes that a link between the incidents remains unproven.