There are 3 security software categories that you should be aware of, but there are different guidelines for Mac users & PC users. We'll start with PC users. (please see the bottom of this email for definitions of the 3 types of security software)

PC Users

1.) Anti-Virus Software:

There are many and varied opinions on the “best” anti-virus software and many “lists” ranking them. To conduct your own research, Do a Google search for “Best AntiVirus Software.” Be careful to avoid “paid” reviews. In my opinion, here are your best options:

Best OVERALL AntiVirus Software for Windows:

Kaspersky Internet Security ($40)
http://usa.kaspersky.com

Best FREE AntiVirus Software for Windows:

AVG Free AntiVirus
http://free.avg.com/ww.download?prd=afe

2.) Anti-Spyware

Many anti-virus software programs also have anti-spyware functionality, but if yours doesn't, you should use the free Spybot Search and Destroy. ( http://www.download.com/Spybot-Search-Destroy/3000-8022_4-10122137.html)

3.) Firewall Software

The best (and most stable) firewall software for Windows is built-in to your operating system (Windows XP SP2 and above). It is turned on by default; leave it on. If you use something like Symantec Internet Security (an all-in-one package which includes anti-virus features as well as firewall software), I recommend turning off the Symantec firewall and using the built-in Windows firewall (do not have 2 firewall programs running on your computer at once).

Mac USERS:

1.) Viruses on a Mac:

Discussions about the Mac virus issue have raged for years without resolution. 2007 saw 5.5 million new PC viruses, and only 2 new Mac viruses. In total, there have been about a dozen Mac viruses since the advent of Mac OSX. A few of these have been potentially dangerous, but most have been fairly innocuous, and about half of them are “proof-of-concept” viruses written by honest software engineers and were never meant to cause harm. They all have proven difficult to replicate themselves, relying on much more “user interaction” than PC viruses (i.e.: you have to do something stupid to allow them to infect you, such as entering your password for no apparent reason). For a full list of Mac security threats since 2002, see this web page: http://www.securemac.com. Realize that all security threats listed on this page have been addressed by Apple's Software Update.

There are a number of anti-virus software programs for Macs, but In my opinion, using anti-virus software on a Mac is like protecting yourself from an attack by a Siberian tiger; they exist, but the likelihood of an attack by one is incredibly remote. If you are worried about getting a virus on your Mac, your best action is to simply keep your computer system software “updated.”

If you feel you must have something to scan your Mac for viruses, use Leopard Cache Cleaner (http://www.northernsoftworks.com/leopardcachecleaner.html) It will also run many other useful repair and “housekeeping” utilities. And remember, if you have a new Mac that can run Windows, you can still get a Windows virus, but only within Windows.

2.) Spyware on a Mac

Pretty much the same can be said for spyware threats on a Mac; our 'Siberian tiger' analgy applies here also. However, there is one thing you should do to protect yourself against the miniscule threat. Turn off the 'Open "safe" files after downloading' option in Safari (Safari—>Preferences—>General), which increases the chance that any new exploit-laden file could have a clear shot at the system.

 

Note: Firefox does not allow this action. "Safe" files will not be automatically opened. And again, keep your system software updated.

3.) Firewall Software on a Mac

A Firewall is software running on a computer which inspects network traffic passing through it, and denies or permits passage based on a set of rules. Again, this is not nearly as urgent on a Mac, but at the very least, it can let you know when an application on your computer is accessing the internet in some unconventional way. For instance, when Microsoft Word tries to update itself, it ‘phones home' to Microsoft to check if there any new updates available. Firewall software will notify you of this action and ask you if you want to allow or deny this action. In other words, do you want to allow another computer on the internet to access information on your computer? In this case, as in most, you'll want to allow the action. However, sometimes a possibly suspicious web page that you access will want to do the same thing. If you do not have firewall software turned on, you'll not be alerted to the attempt to “check” something on your computer. Not good.

Mac OS 10.5 (Leopard) has an acceptable firewall built in, and is adequate for most users. It's off by default, but to turn it on, go to System Preferences-->Security-->Firewall and click “Set access for specific services and applications.” From then on, each time a computer on the internet attempts to connect to your Mac, you will be asked if you wish to “allow” or “deny” the action.

If you want more robust and flexible control of your firewall, try Little Snitch for Macintosh ($30). http://www.obdev.at/products/littlesnitch/index.html

The Three Security Software Categories with Definitions (This is a simplification)

Viruses, Worms & Trojan Horses – Programs that can copy themselves and infect a computer without permission or knowledge of the user. They spread from one computer to another over the Internet, or by carrying them on removable media such as a CD, or USB drive. They generally cause only “vandalistic” harm.

Spyware - Programs that collect various types of personal information, such as Internet surfing habit or sites that have been visited. They can also interfere with user control of the computer, such as installing additional software or redirecting a web browser. Spyware can change computer settings, resulting in slow connection speeds, changing home pages, and loss of Internet or other programs. Their main purpose is to make money for the authors as opposed to simply causing vandalism. Together, viruses, trojan horses, worms and spyware are generally referred to as Malware.

Firewall Protection - is software running on a computer which inspects network traffic passing through it, and denies or permits passage based on a set of rules. When properly installed and configured, firewall software can (but not always) prevent the other 2 types listed above from causing harm to your computer.