As the title states, I'm wondering if someone could give me an in-depth description of how to gain admin access to servers.
When you hack a system, especially early on, you're already gaining admin access. Simply get a valid log-in for the "admin" account. There are other types of accounts on banks and government registries.
The problem is, your log-in credentials might be revoked when the company next checks for security breaches. This can happen if:
However, gaining administrator access for setting up a bounce is typically not worth it. I'm not entirely sure whether it's a certain number of bounces, or if it's just that the bounce logs are suspicious (because of passive traces), but sooner or later your admin access will be revoked if you abuse the system as a proxy.
Exceptions which will let you keep your admin access indefinitely are:
InterNIC also never changes passwords, but for some reason does not count as an admin access bounce node.