A new report traces a large cybersecurity threat group to China’s People’s Liberation Army. The group, called APT1, is one of the most persistent of China’s cyberthreat actors. It has compromised 141 companies since 2006, according to Mandiant. The nature of the work of “Unit 61398″ is considered by China to be a state secret, but Mandiant said it believes it engages in harmful computer network operations. China’s Foreign Ministry said the nation is firmly opposed to hacking, and has supported regulation to prevent cyberattacks.”]