A significant data breach at Knownsec, a Chinese cybersecurity firm linked to the government, has exposed over 12,000 classified documents, revealing advanced state-sponsored cyber weapons and a global target list. The breach, which came to light on November 2, 2025, is one of the most severe in recent years, highlighting vulnerabilities within a company that plays a crucial role in China's national security. The leaked files contained technical details of hacking tools, operational collaborations, and a list of foreign surveillance targets. Among the staggering data theft were 95GB of immigration records from India, 3TB of call records from South Korean telecommunications provider LG U Plus, and 459GB of road planning data from Taiwan. The leaked documents identified over twenty countries as surveillance targets, including Japan, Vietnam, and the UK. Knownsec's technical capabilities, exposed in the breach, included a library of Remote Access Trojans for various operating systems and hardware-based tools like a malicious power bank designed to covertly extract data. In response to the fallout, Chinese Foreign Ministry spokesperson Mao Ning denied knowledge of the incident while reiterating China's opposition to cyberattacks. This statement failed to clarify the government's involvement in cyber operations, which may be perceived as legitimate national security efforts. The breach provides an unprecedented look into state-sponsored cyber activities, offering valuable insights for global cybersecurity defenses while raising serious concerns about the security practices of firms handling sensitive government information.