Mac OS X is fairly secure straight out of the box. Nonetheless, there are a few steps you should take to help keep your computer safe.
Keep Your System and Software Up to Date
This is one of the easiest, most effective things you can do to keep your computer secure. The automatic update tool is in System Preferences under the apple menu in the top left corner of your screen. Click Software Update, and then choose whether you want to update manually or automatically.
If you run common applications such as the Microsoft Office suite, check the Office Update page regularly. Microsoft Office applications frequently need security patches.
Install Antivirus Software
While Mac OS X is not as susceptible to viruses as some other operating systems, you should still install antivirus software to help alert you to viruses in email messages or downloads. Even if the virus doesn’t affect Mac OS X, you don’t want to pass it on to friends, family, or colleagues who may be using a different operating system.
Don’t Run Services You Don’t Need
Each service you run represents a means of access to your computer. That’s not inherently bad, but there’s no need to expose yourself to unnecessary risks. If you don’t need to run a web service on this computer, don’t start it up. The list of available services can be found in System Preferences under the Services tab of the Sharing icon. Be especially wary of the sharing services; a misconfiguration here could grant full access to personal files or system resources.
Choose a Good Password
Any computer that has multiple users or is attached to a network needs to have good password protection for each user.
Use Your Personal Firewall
While the firewall included in Mac OS X is not nearly as customizable as other software firewalls, it is effective in reducing the amount of network traffic that is allowed to reach your computer. Open System Preferences and click the Sharing icon. Next, click the Firewall tab and then click Start.
Limit Administrative Access
Mac OS X allows you to designate certain users as system administrators. These users are allowed much greater access to the system, meaning that you should be careful when granting these privileges. If a user doesn’t need to modify the system’s settings, there is no reason for that user to have administrative access.