In October 2018, Bloomberg recounted a Chinese supply-chain attack on Supermicro motherboards used in servers for Amazon, Apple, and more than 20 other companies. https://www.bloomberg.com/news/features/2018-10-04/the-big-hack-how-china-used-a-tiny-chip-to-infiltrate-america-s-top-companies

This presentation demonstrates how I replicated it, on a Cisco firewall, with a shoestring budget, and how you can, too.

You may have seen a preview of my work in an article in Wired by Andy Greenberg:
https://www.wired.com/story/plant-spy-chips-hardware-supermicro-cheap-proof-of-concept/