The best way to secure any computer that way is just to unplug it.
Security threats have been around and will continue to exist, and that's something you have to understand.
However there are a few tips, costumization that you can do to have a more secure box.
A lot of these security measures are present in a wiki here: Ubuntu Security
Here you will find an introduction to the most famous forms of attack and how to prevent them, including:
Introduction to AppArmor
Host-based Intrusion Detection Systems (HIDS)
Network Intrusion Detection Systems (Snort)
Viruses
SSH and VNC
Firewall
etc.
Luckly, there are a few good resources where you can learn more:
The best way to secure any computer that way is just to unplug it.
Security threats have been around and will continue to exist, and that's something you have to understand. However there are a few tips, costumization that you can do to have a more secure box.
A lot of these security measures are present in a wiki here: Ubuntu Security
Here you will find an introduction to the most famous forms of attack and how to prevent them, including:
Introduction to AppArmor
Host-based Intrusion Detection Systems (HIDS)
Network Intrusion Detection Systems (Snort)
Viruses
SSH and VNC
Firewall
etc.
Luckly, there are a few good resources where you can learn more:
Security
My favorite site for security
InstallingSecurityTools
The Big Ol' Ubuntu Security Resource
Locking Down Ubuntu
Basic info
Because there are so many measures one can take reading for those sites is a good place to start. I can resume some of the basic measures:
sudo chmod 0700 /home/your-user-name
Also there's an Ubuntu version called Ubuntu Server that you should try.