On: Yes, I was hacked. Hard.

[0x0]

How would it connect to the iCloud services? The mac doesn't have a built-in 3G connection, so the only way it can go online is through previously-stored wifi associations.

[tres → 0x0]

my solution to this is to have an auto-login non-admin account on the machine that's not my own account.

Give them enough access to get on the internet & use the machine. Keep my files stored in my own account.

[Timothee → tres]

I enabled the guest account on my Mac, but auto-login in non-admin account is a good idea.