I hate when security folks say "attackers only have to win once, defenders have to win every time" because it's flawed thinking.
Thanks @haroonmeer for this: "Actually, an attacker can win everywhere and as a defender you only have to find them once"https://youtu.be/Wqww0BRIX5U
But you do have to find them, not just a IP or an addresd but physically lay hands on them & then make sure they are stopped Otherwise they will be back as someone else in no time