Dec 13 (Reuters) - A hacking group named APT5, which is suspected to be Chinese, has exploited a vulnerability in networking gear from U.S. technology company Citrix Systems Inc to spy on targets. A U.S. National Security Agency advisory on Tuesday reported the activity and requested that victims who discover additional evidence of an attack reach out to the NSA's Cybersecurity Collaboration Center, a unique division of the spy agency opened in 2021 with the mission of public-private sector collaboration. Citrix in a blog post said it was "aware of a small number of targeted attacks in the wild using...