Single attacker uses AI tool ARTEX to breach multiple South Korean banks

a suspected chinese-speaking attacker used artex, a chinese open-source tool that uses ai language models for automated penetration testing, to breach multiple south korean financial institutions between late september and early october 2026. the attacker stole more than 25,000 records from shinhan bank alone, including names, contact details, income, and credit limits. the models behind artex were deepseek v4.1-flash, glm-5.3, and grok 4.6. researchers found claude code session logs on the attacker's open directories, showing searches for telegram groups to sell stolen data. this incident highlights the cybersecurity risks associated with ai tools, which can enable a single person to pull off massive breaches in a short window.