https://www.techradar.com/news/apple-and-amazon-deny-allegations-of-server-tampering-by-chinese-agents

A report published last week by Bloomberg Businessweek claimed that China had infiltrated servers of 30 US companies, including Apple and Amazon. 

The report cited 17 anonymous intelligence and company sources claiming Chinese operatives had tampered with a “technology supply chain”, managing to place computer chips inside equipment that was shipped to the companies. This would give China easy access to secure company networks, however, both tech giants have vehemently denied the allegations.