US cybersecurity firm CrowdStrike said an unidentified hacker believed to be a Chinese speaker used artificial intelligence-powered hacking tools to breach multiple South Korean financial institutions and steal data.
In a report released Wednesday, CrowdStrike said the attacker used ARTEX, an open-source AI-powered penetration-testing tool developed in China, alongside large language models to carry out cyberattacks between late September and early October.
The findings come amid a series of data breaches at South Korean financial institutions, including Hana Bank, KB Kookmin Bank and Shinhan Bank, prompting financial authorities and investigators to launch probes into the incidents.
According to CrowdStrike, the compromised systems included a bank's loan inquiry service used by financial brokers and another bank's mobile work-support system for employees.
"While this activity has not been attributed to a named adversary, the threat actor is likely a Chinese speaker and financially motivated," CrowdStrike said in the report.
"This assessment is made with moderate confidence based on the use of the Chinese-developed tool ARTEX and observed Chinese-language prompts."
The cybersecurity firm said the attacker primarily used DeepSeek v4.1-flash, supplemented by GLM-5.3 and Grok 4.6 through Claude Code sessions.
In one Claude Code session, the attacker asked Claude to draft a security researcher resume using personal details, including an age of 26 and an educational background at South China University of Technology in Guangdong, China.
However, the attacker's identity, the full extent of the breaches and the amount of stolen data remain unconfirmed.
CrowdStrike also identified two servers used in the attacks: one based in Hong Kong serving as the attacker's primary infrastructure and another hosting ARTEX, which was likely used to target South Korean financial institutions.
An analysis of files showed the attacker asked Claude about marketplaces for stolen South Korean data and Telegram groups involved in selling such information, suggesting a possible financial motive. (Yonhap)