There are many findings that GuardDuty triggers on, and with that, there are many ways to bypass those detections so that you do not get caught. Not everything can get bypassed, but as an attacker, you should at least understand what GuardDuty is looking for so that you can actively work to avoid or bypass it as you attack an environment. It is possible that just a single GuardDuty alert on your activity could shut down your access to the account, but it is also possible that no one is really paying attention to the alerts as they come in, so you won't need to worry as much in that situation.
If you wanted to get really advanced with it, you could also purposely trigger certain GuardDuty alerts to send any listening defenders on wild goose chases, while you are secretly doing something else in the environment. Along with this, if you know that the target...