Until recently, the cyber attacker methodology behind the biggest breaches of the last decade or so has been pretty consistent:

Compromise an endpoint via software exploit, or social engineering a user to run malware on their device; 
Find ways to move laterally inside the network and compromise privileged identities;
Repeat as needed until you can execute your desired attack — usually

Until recently, the cyber attacker methodology behind the biggest breaches of the last decade or so has been pretty consistent:

Compromise an endpoint via software exploit, or social engineering a user to run malware on their device; 
Find ways to move laterally inside the network and compromise privileged identities;
Repeat as needed until you can execute your desired attack — usually