Bruce Schneier comments on Rob Joyce’s public comments on NSA’s Tailored Access Operations – how they hack into whatever they want access into.
It’s profitable to know this sort of methodology since it isn’t unique to the NSA. Any APT or hacker can use these techniques.
EDITED TO ADD (2/2): I was talking with Nicholas Weaver, and he said that he found these three points interesting:
A one-way monitoring system really gives them headaches, because it allows the defender to go back after the fact and see what happened, remove malware, etc.
The critical component of APT is the P: persistence. They will just keep trying, trying, and trying. If you have a temporary vulnerability — the window between a vulnerability and a patch, temporarily turning off a defense — they’ll exploit it.
Trust them when they attribute an attack (e,g: Sony) on the record. Attribution is hard, but when they can attribute they know for sure — and they don’t attribute lightly.