"nobody" in local@localhost - / also called Unauthorized user...

Question

So I had a hacker crawl up through the wiring and play merry **** with my machine for mischief. I moved, changed ISP's, run in stealth, and they're back!
Found tonight they were in spotlight poking around. No account on Log In, but unauthorized user "nobody" is listed here and there in the guts... Is this a name for the Mac's personal use? Or some parasite to delete and watch out for?
Other hacker traces appreciated... These are, I suspect, people I know vaguely- and malicious as ****.

Answer 1

When you decide to reconfigure your computer's setup, perhaps
after an all new installation where you can choose different user
accounts, privilege levels and then decide to not use the Admin
account as a daily user, then you may have an additional level
of security and assurance in using your computer.
You need not set up a Mac to run with your name as Admin and
that account need only be adequate enough to install, upgrade
the system, install applications, do preventative maintenance
and periodic updates, security update and so on; otherwise,
one may actually use a second account as daily user and have
the computer see that one as the primary. The main Admin PW
would still be for the original setup account, but your own daily
use would be under a different password and perhaps even an
account with less privileges.
By doing this, it is also possible to have a third or fourth account
and let other people log in to a guest account with little or no
access to most things in the computer. Isolating access by default.
I've set up a few OS X computers this way, and the main user is
something simple, such as iMac G4 User; and the registration is
not the kind of thing that would need to be registered online w/Apple.
The computer then is "iMac G4 user's computer." This makes it easy
to setup a computer, fully upgrade it, and also isolate the admin acct
from further tampering since it won't be the defacto boot account.
There are a few levels of access and privileges can be customized.
So, if access has been a problem, there is the Firewall and there
are accounts which may be used daily, which do not automatically
give anyone the rights to change the system or get into the Admin
account. You may have to login at bootup, or other secure devices
if you leave the computer physically available to other persons.
Most of this kind of information is available either in Apple Support
or in other Mac user web sites where security is discussed.
In any event...
Good luck & happy computing!
{ edited to ad a space between every word }