Chinese hacker breached South Korean banks with ARTEX AI and Claude agents—exposing 144,000 customer records

A Chinese-speaking hacker launched a sophisticated cyberattack campaign against South Korean financial institutions in late September and early October 2026, using an open-source AI-powered penetration testing framework called ARTEX AI and Claude agents to automate reconnaissance, identify vulnerabilities, and exfiltrate customer data. Security researchers at CrowdStrike confirmed that the attacker compromised at least five to seven tier-one South Korean banks, including Shinhan Bank, KB Kookmin Bank, Hana Bank, Yegaram Savings Bank, Welcome Savings Bank, and BNK Busan Bank, exposing the personal and financial data of between 68,000 and 144,000 customers depending on how affected institutions count their victims.