anti virus on a mac

The MAC has been far less troubled by malware than the PC world BUT it is still an issue. In the General tab there is "Allow Apps downloaded from:" and then there are 3 options. If you choose Mac App Store & Identified developers you will be ultra safe.

However there may be quite a few programs you want to downlaod that do not meet that criterea so the you have a choice to turn it off temporarily. For example I had to turn it off to download a prog called Phocus from the Hasselblad camera people. I trust them.

I think however you can sleep safe unless............

And you have been well informed. A modicum of caution is all that is generally needed.

Macs are not absolutely safe from infection but as of now there are no grounds to fear otherwise. You do not need virus protection but it is wise to have ClamXav in your applications folder for checking out anything you suspect ... and that's just about all.

So go and enjoy your Mac.

There are many forms of ‘Malware’ that can affect a computer system, of which ‘a virus’ is but one type, ‘trojans’ another. Using the strict definition of a computer virus, no viruses that can attack OS X have so far been detected 'in the wild', i.e. in anything other than laboratory conditions. The same is not true of other forms of malware, such as Trojans. Whilst it is a fairly safe bet that your Mac has NOT been infected by a virus, it may have another security-related problem, but more likely a technical problem unrelated to any malware threat.

You may find this User Tip on Viruses, Trojan Detection and Removal, as well as general Internet Security and Privacy, useful:

https://discussions.apple.com/docs/DOC-2435

The User Tip (which you are welcome to print out and retain for future reference) seeks to offer guidance on the main security threats and how to avoid them.

More useful information can also be found here:

http://www.reedcorner.net/mmg/

Hello:

You have already received some good information.

I have been using Macs for...perhaps 17 years. I have never used A/V software since OS X 10 was released many moons ago. I never say never, and I have a really good backup/recovery plan. However, using A/V software on a Mac essentially wastes resources (IMHO).

Barry

This comment applies to malicious software ("malware") that's installed unwittingly by the victim of a network attack. It does not apply to software, such as keystroke loggers, that may be installed deliberately by an attacker who has hands-on access to the victim's computer. That threat is in a different category, and there's no easy way to defend against it. If you have reason to suspect that you're the target of such an attack, you need expert help.

Alll versions of OS X since 10.6.7 have been able to detect known Mac malware in downloaded files. The recognition database is automatically updated once a day; however, you shouldn't rely on it, because the attackers are always at least a day ahead of the defenders. In most cases, there’s no benefit from any other automated protection against malware.

Starting with OS X 10.7.5, there is another layer of built-in malware protection, designated "Gatekeeper" by Apple. By default, applications that are downloaded from the network will only run if they're digitally signed by a developer with a certification from Apple. Applications certified in this way haven't actually been tested by Apple (unless they come from the Mac App Store), but you can be sure that they haven't been modified by anyone other than the developer, and his identity is known, so he could be held responsible if he knowingly released malware. For most practical purposes, signed applications can be considered safe. Note, however, that there are some caveats concerning Gatekeeper:

1. It doesn't apply to software that comes packaged as an installer. Treat all third-party installers with caution.
2. It can be disabled or overridden by the user.
3. It can be bypassed by some third-party networking software, such as BitTorrent clients and Java applets (see below.)
4. It only applies to applications downloaded from the network.

Notwithstanding the above, the most effective defense against malware attacks is your own intelligence. All known malware on the Internet that affects a fully-updated installation of OS X 10.6 or later takes the form of so-called "trojan horses," which can only have an effect if the victim is duped into running them. If you're smarter than the malware attacker thinks you are, you won't be duped. That means, primarily, that you never install software from an untrustworthy source. How do you know a source is untrustworthy?

1. Any website that prompts you to install a “codec,” “plug-in,” or “certificate” that comes from that same site, or an unknown one, is untrustworthy.
2. A web operator who tells you that you have a “virus,” or that anything else is wrong with your computer, or that you have won a prize in a contest you never entered, is trying to commit a crime with you as the victim. [Some reputable websites did legitimately warn users who were infected with the "DNSChanger" malware. That exception to this rule no longer applies.]
3. “Cracked” copies of commercial software downloaded from a bittorrent are likely to be infected.
4. Software with a corporate brand, such as Adobe Flash Player, must be downloaded directly from the developer’s website. No intermediary is acceptable.

Linc Davis said it correctly, I can't agree more!!

You need to be careful with third party installers from companies and cracked software... quite often (not always) are prone to carry malware of some sort.

This being said, you may not affect your system but if connected to a network could pass on unknowningly a piece of software designed to infect networks or launch an attack.

ClamXav is excellent at detecting such Malwares.