Trend Micro study: Most attacks against industrial systems start in China. Chinese hackers often come back to try additional exploitations if the prior attempts failed. U.S. was a distant second at 19 percent, followed by Laos at 12 percent. Trend Micro: “Disable Internet access to your trusted resources, where possible” The No. 1 recommendation: “Disabling Internet access where possible,” the report says. The report contends industrial systems can be defended from such attacks, and offers 20 recommendations.”]
Source: https://www.cuinfosecurity.com/blogs/china-after-more-than-ip-p-1441