Linux Privilege Escalation – (running) Services [closed]

Linux Privilege Escalation – (running) Services [closed]

Since I'm quite new to the whole topic of linux privilege escalation I've done a few courses in which usually the enumeration of services is mentioned with commands like:

ps aux
systemctl --type=service --state=running

But I wonder how do I go an from there? How do I find vulnerable services, and even if there are no (usable) CVEs or Exploits for those services, how can I check for service misconfiguration?

I'm interested both in tools but more importantly in a methology to proceed.