A leading cybersecurity firm says it has discovered a “highly sophisticated” piece of malware being used by Chinese hacking teams to attack government and critical infrastructure targets. Symantec, a division of U.S.-based software designer and manufacturer Broadcom, said the earliest known sample of the malware, which has been dubbed Daxin, dates back to 2013, while Microsoft first documented the hacking tool in December 2013. A report by the company’s Threat Hunter Team says Daxin is “without doubt” the most advanced piece of malware it has seen used “by a China-linked actor.” The unit says Daxin was discovered along with other…