As for covert ops, well, they're covert. I don't have any evidence (hence I said "I'm guessing") but that's how I understand secretive agencies do things. If you look at all of the agencies involved in Stuxnet, you'd get the idea that allied countries' secret services tend to work together (or for each other) to some degree when it suits them.
There's many such cases. They're well known for spying on Siemens as well. With allies like the United States, who needs enemies?
[1] https://www.spiegel.de/politik/ausland/wikileaks-enthuellung...
There was also inferences that they penetrated Huawei.
I might be willing to give you Huawei if you cite a source. They're a gray area (by design) due to China's strategy of military-civil fusion.
Given hacking means unauthorized access to data, can you explain how intercepting confidential documents in an unauthorized manner could not possibly meet the definition?
Additionally, we know much more detail on Siemens, including the planting of malicious code, which absolutely meets any definition of hacking. [1]
Also remember the Google sniffing?
https://www.theregister.com/2013/11/07/google_engineers_slam...
When does the US attack private enterprise?