How can I download and install software and make sure that it is not infected with viruses, malware or a keylogger?

Also, I heard that Macs "don't get viruses". Is this true? Is it a good practice to run virus software on a Mac?

4 Answers 4


Nope it's not true, by design Mac has a better security model than Windows, but that doesn't mean it's secure. Furthermore due to the market share of Apple growing more and more chances are that Mac will get more interest from attackers than they currently have due to the growth of potential targets.

There have been virusses for Mac in the past like the Trojan BackDoor.Flashback which specifically targetted a Java exploit within OS:X.

I would indeed run anti-virus software on your Mac, it provides an extra layer of defense.


Short answer

First, it's not true: Macs and any other OS can get viruses. Just few viruses are written for mac.

Yes, it's a good practice to run antivirus software on a Mac.

How to download and install software that isn't infected: in general, you get good software from good sources, and checking that the software you just download wasn't tampered with (man in the middle attack). For example, checking if the MD5 checksum is the same the site published.

Longer answer

You just could be sure that the software is free of bugs, keyloggers, virus, etc., if you are able to inspect the source code, and know how to do it, since there are some techniques that can make malicious code less evident.

And you would also need to trust that Apple made the Mac without virus, keyloggers, and etc. And that it didn't allow NSA put any backdoor inside it. And that no programmer could make it inside the OS. And that the chips manufacturers (not only the processor, but almost every chip used inside) didn't include some hardware trojan, keylogger, etc.

  • 1
    Software might be legitimated and still have security holes which get exploited by attackers. Nov 25, 2013 at 11:55
  • if he did ask about security holes explitable by 3rd parts, I would agree with you. He asked about software that comes with keyloggers, virus... Nov 25, 2013 at 11:57
  • he also asked if Macs are vulnerable to virusses in general. Most virusses are in fact using known security vulnerabilities to get in or to elevate privileges. Nov 25, 2013 at 11:58
  • hum, and isn't that what I answered in the first two paragraphs??? Nov 25, 2013 at 11:59
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    Note that iOS does have some backdoors used for diagnostics ... allegedly. I wouldn't exclude Macs as well, so.
    – edmz
    Feb 5, 2015 at 14:41

I'll do my best to deal with your first question, since people mainly discussed the second and third ones you asked--and respectfully those are simple matters of fact, and subordinate logic. Yes you can get malware/viruses (it is increasingly common, much more than Apple wants to admit), and therefore yes you want to protect yourself from that stuff.


1. Lock down the Internet

  • Set up a firewall (obvious).
  • If you want to really manage connections, try Little Snitch (and buy it if you feel like it; it is at least an eye-opener about what's connecting to your computer and what your computer is sending out).
  • Use an updated, modern browser (I would go with Firefox), with plugins like Ghostery/AdBlocker/HTTPSeverywhere, that limit the amount of malicious stuff that could come in through your browser. You do not actually have to click download and install to get a virus anymore on an Apple product :(
  • Check your extensions, defualt search engines every once in a while. New extensions and changed default search engines are really obvious indicator that some unwanted monkey business is taking place on your system.
  • Obviously, dont install software you don't trust and avoid piracy (if you can afford it). Pirated software is rife with malicious stuff even in the Apple Universe.
  • Also a no-brainer, avoid public networks if you can, and don't set your device to auto-connect to open ones (as they might by default--I haven't bought a new machine in a while, but they used to do that I believe).
  • Turn off any sharing/bluetooth stuff you don't intend to use under Sharing.

2. Avoid Physical Media Vectors of Attack

  • Don't use USB drives on a lot of different machines. They are an increasingly common vector for infection. In fact, try not to use them. There are methods of sending large files and the internet is pretty fast. If you can email it to yourself, do it. With email, you can be sure that nothing is piggybacking on the drive; and your email client should run some antivirus on the file itself. So that's better.

  • Don't charge your phone from your home computer's usb drive. Phones are increasingly affected by viruses, just from browsing on 4g networks, and can transfer them to your machine nowadays. You can back your contacts up on the cloud, if you have some data-driven desire to connect the two devices. Take advantage of the cloud, and your much-faster charging wall charger.

  • If you feel the need to use your home computer or (much worse) your work computer to charge your phone on your desk, then come home, and plug that into your home computer... perhaps consider buying a nifty data-only usb adapter from Amazon. Documents at work get passed from hand to hand, inside and outside the company... yeah the local network can be full of problems... and IT departmetns tend to be behind the 8 ball on security. You can't even necessarily install things on a work computer, to even make sure that it's kosher. Yeah. This is an idiot proof solution.

3. Utilize Anti-Virus and Anti-Malware Software -- The Belated Meat of this Post

  • Malware: no one program works best. As in the PC Universe, you need to run a few to catch everything reliably. I like Adware Medic (and apparently so do Apple Support folks from my troubleshooting sessions) and BitDefender's Adware Removal Tool. They have each caught programs the other one missed, and they are super lightweight-fast, and free.

  • Anti-Virus. Just like with Malware, you want to use more than one program. I can't actually recommend two. I have a half dozen, and I don't like most of them. One which I would use is ClamAV. It's not rated the best by reviewers (maybe because nobody is paying them to review it well), but in my exprerience, it has caught more infected files than the other ones. If you download the version from their website, you can schedule it to auto-update and auto-run--for some reason the mac store version doesn't seem to have this feature.

4. Lock the Screen, Use A Strong Password

  • Sleep your screen when you leave your desk, and set it to require a user password after a few seconds of sleep (System Preferences --> Security & Privacy). Also, under Power Settings, set your computer to go to sleep after it is idle more than a few minutes. This will cover you decently, if you walk away from your machine in the office, and forget to sleep it.

  • Install/use Caffiene to toggle the sleep/lock behavior on and off, when you want to watch a movie or need to give a presentation. It's easier. And easier than manually changing the time-to-sleep when you need to do it, and therefore you're way less likely to get fed up safe practices and switch your sleep time back to "never."

5. Familiarize Yourself With Running Processes and Learn to Use the Command Line

  • You don't have to be a ninja about it. But you can take note of running processes in the activity monitor, and google new ones that pop up with fair ease. You would do the same thing on a PC really...

  • If you really need to be certain that you don't have some kind of keylogger (some companies install them on work machines and you're not necesarily allowed to remove them), you will probably need to pick up some familiarity with the terminal. Which is a whoooole different topic. $Man ps. and... well, take things from there lol.

  • "Use an updated, modern browser (i.e. not Safari)..." I fail to see why Safari is not a modern browser by today's standards. Is Google Chrome somehow better because it sends your personal data back to Google which then uses it to track you through advertising and searches somehow more "updated" and "modern"?
    – ajkblue
    Feb 6, 2015 at 3:54
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    I'm not going to get into a flame war about the One True Browser. Apple is late on security updates, denies security issues exist, and I don't trust them. Also, it's not as widely adopted as other browsers, so you don't have the same awesome privacy extensions. Also, it kind of sucks. I'm running 10.10 w/updated safari (no extensions) and it randomly shits the bed loading webpages. So I just never use it. Firefox is good, imo. Google is fine, to me. Because I use google, and Google's DNS it knows everything anyway. It's keyloggers and external parties that worry me.
    – sas08
    Feb 8, 2015 at 1:49
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    The advantage of Chrome (despite it's disadvantage of sharing your data with Google) is that they autoupdate critical plugins for security vulnerabilities. Unless you don't use google email, google docs, google search, or google DNS (and btw nslookup where you're getting your IPs from anyway... it's all frigging government servers) worrying that Google is going to learn anything it didn't already know about you is kinda wild.
    – sas08
    Feb 8, 2015 at 1:52
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    That makes sense. It just didn't apply to me as I don't use any Google services, as I do not trust Google. (I use DuckDuckGo myself) I agree that Firefox is good as well, with many extensions and is used by the Tor project. Glad we could come to an understanding. :D
    – ajkblue
    Feb 8, 2015 at 2:29
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    Appreciate that too--I note in ref. to the above that Safari is working better with a Keychain First Aid run and deletion of expired certs... which Google must have some smarter way of handling? An issue no doubt for many older machines in use. I'm probably veering off topic to the original post, but I would add that I am interested in absolute security/privacy... and creeping your profile's followed convos has been quite informative for me with regards to that. So, yes, glad that you commented. Respet.
    – sas08
    Feb 9, 2015 at 17:21

Download trustable software

Only download softwares which you find an md5 or sha1 checksum available on a publicly visible server and whith a clear timestamp. Hence if the software was corrupted (by whatever you imagine) then it is very easy for anyone to detect this corruption. Such a corruption will be brought back to the attention of the editors within less than a few hours.

If you can't find such a publicly visible checksum, just download softwares from editors who are providing them through https:// and moreover from editors who explain publicly how they do protect their internal servers from attacks. (An https:// download of a virused software is a sure way to get an intact virus).

Mac's don't get viruses

Mathematically wrong. Their software is of varying quality, sometimes much better than many, sometimes the other way around. MacOS X is based on a rather strong solid OS: FreeBSD, but the GUI added on top is including too many functions to maintain a high quality level. Too many functions mathematically increases the probability of internal weaknesses. MacOS X is simply conceived by human with the same probability of comitting errors. Even quality controls may contain errors.

Anti-virus on Mac

Yes this is clearly a good policy: an anti-virus on any computer.

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