Very plausible as we know nothing is secure. Encryption is broken so getting info from others would be very easy with the correct tools / programming skills.
Interesting read about the student worm and uranium Inrichment plants: stealthy and persistent. If this can be accomplished, so can a shit load of other stuff that no one is aware of - hey vault 7 and thehackingteam - shadow brokers.
Old but very relevant
https://www.quora.com/What-is-the-most-sophisticated-piece-of-software-code-ever-written