Open-source penetration-testing agent reportedly used in breach campaigns in Japan and South Korea

A post citing Bloomberg says an open-source agent built for authorized penetration testing became a shared engine of breach campaigns in Japan and South Korea within weeks. It says Ierae examined an attack server that targeted about 20 companies, almost exclusively in Japan; nine worked in the same industry. In South Korea, CrowdStrike tied the tool to a likely Chinese-speaking, financially motivated actor who ran it mainly on DeepSeek v4.1-flash against financial firms from late September, according to the post.