We had remote access to their networks at times. My very first day I was amazed how much access I had at will.
One day it was announced that a customer had come to us and demanded everyone had to meet X requirements to be able to work on their networks.
Not long after another financal institution made a similar request.
Some folks inside the company were a bit riled up by the requirements (background checks, some other things). They felt the requirements were absurd.
Considering the access we had I thought they weren't strict enough. As just a lowly support dude hired during the dot com boom because the company needed warm bodies (who could do some independent thinking / troubleshooting) ... I had a lot of access.
I don't know if they were thinking about spying like this, but I'm always amazed how much access people have to data and etc just from a technical support perspective (forget developers...).
Later the company outsourced support to other countries... I'm not even sure you need spies in the US / would know anyone was spying under those circumstances.
Support teams are probabbly a hell of a lot cheaper / easier to infiltrate / they get little / poor management / oversight. I saw tons of strange choices by our outsourced technical support staff, every single time I raised concerns it was discarded by something to the effect of "yeah they suck".
And that doesn't account for all the financial institutions who outsourced their own direct ops teams to other countries ... I'd call them and if they ever were capable of following instructions 9x out of 10 they'd open up the wrong network / modems / etc.