Yes, I almost mentioned the Belgacom sysadmins in one of my responses.
How many people here work for Google, Facebook, Apple, etc? What if you could compromise their workstations and get privileged access to the backend of social networks, email systems, etc? We are being actively hunted and there's evidence of that.
Some years ago FreeBSD had an intrusion via one of the commiter's machine or stolen SSH key, I don't remember which any more, but I do remember that it took months for the package building infrastructure to get fully operational again. I think they never got to the bottom of that (who did it or why). Linux had a very similar incident if I'm not mistaken.
It's such a standard and effective method in human intelligence, that it's extremely naive to think an analogue wouldn't be used extensively in signals intelligence too.
How many people here work for Google, Facebook, Apple, etc? What if you could compromise their workstations and get privileged access to the backend of social networks, email systems, etc? We are being actively hunted and there's evidence of that.