The news isn’t that they’re doing it, but that the documents detail how they do it. Disclaimer: I haven’t read the article yet, I’m basing this on the title.

It is at least somewhat interesting that there is so much state-sponsored attacking going on that the incidence of two different states/teams ending up on the same box is not only non-negligible, but even common.

It also makes you wonder why it isn't commonplace to harden targets against the exploit that was used to get in, to deny that space to competitors. Perhaps it is, and it's just that there's so many vulnerabilities out there that it's common for multiple teams to break into the same box via different exploits.