Previous 1 2 Next 22 Replies Latest reply: Jan 23, 2016 10:43 PM by riospark
aidan_s_ Level 1 (0 points)


I am a new mac user and i have purchased this macbook pro retina display a few months ago. I do not have any anti virus software on it, and I am just wondering how i would go about checking if there is a trojan horse, virus, or anything of that nature. I do not want to buy a software that does this for me, but i just want to reassure my self that my $1300 investment is safe!

Thank you!

MacBook Pro with Retina display, OS X Mavericks (10.9.2)
  • Glenn Leblanc Level 6 (9,325 points)

    You can't check for viruses without having software to do it with.


    If you feel the need for virus checking software, you can download ClamX AV for free. I've been running AntiVirus software on my mac for 15 years and have never found a virus or trojan. I do have ClamX installed. In reality, virus sofware for macs has done more harm than good.


    But if you are careless on where you go on the internet and download a lot of 3 party software from unknown sites, you may want to look into installing an AV program. Just be very careful on which you choose. Like I said, most do more harm than good.

  • Linc Davis Level 10 (192,644 points)
    1. This is a comment on what you should and should not do to protect yourself from malicious software ("malware") that circulates on the Internet. It does not apply to software, such as keystroke loggers, that may be installed deliberately by an intruder who has hands-on access to your computer, or who has been able to log in to it remotely. 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.
    If you find this comment too long or too technical, read only sections 5, 6, and 10.
    OS X now implements three layers of built-in protection specifically against malware, not counting runtime protections such as execute disable, sandboxing, system library randomization, and address space layout randomization that may also guard against other kinds of exploits.

    2. All versions of OS X since 10.6.7 have been able to detect known Mac malware in downloaded files, and to block insecure web plugins. This feature is transparent to the user. Internally Apple calls it "XProtect."
    The malware recognition database used by XProtect is automatically updated; however, you shouldn't rely on it, because the attackers are always at least a day ahead of the defenders.
    The following caveats apply to XProtect:
    • It can be bypassed by some third-party networking software, such as BitTorrent clients and Java applets.
    • It only applies to software downloaded from the network. Software installed from a CD or other media is not checked.
    As new versions of OS X are released, it's not clear whether Apple will indefinitely continue to maintain the XProtect database of older versions such as 10.6. The security of obsolete system versions may eventually be degraded. Security updates to the code of obsolete systems will stop being released at some point, and that may leave them open to other kinds of attack besides malware.
    3. Starting with OS X 10.7.5, there has been a second layer of built-in malware protection, designated "Gatekeeper" by Apple. By default, applications and Installer packages downloaded from the network will only run if they're digitally signed by a developer with a certificate issued by Apple. Software certified in this way hasn't necessarily been tested by Apple, but you can be reasonably sure that it hasn't been modified by anyone other than the developer. His identity is known to Apple, so he could be held legally responsible if he distributed malware. That may not mean much if the developer lives in a country with a weak legal system (see below.)
    Gatekeeper doesn't depend on a database of known malware. It has, however, the same limitations as XProtect, and in addition the following:
    • It can easily be disabled or overridden by the user.
    • A malware attacker could get control of a code-signing certificate under false pretenses, or could simply ignore the consequences of distributing codesigned malware.
    • An App Store developer could find a way to bypass Apple's oversight, or the oversight could fail due to human error.
    Apple has so far failed to revoke the codesigning certificates of some known abusers, thereby diluting the value of Gatekeeper and the Developer ID program. These failures don't involve App Store products, however.
    For the reasons given, App Store products, and—to a lesser extent—other applications recognized by Gatekeeper as signed, are safer than others, but they can't be considered absolutely safe. "Sandboxed" applications may prompt for access to private data, such as your contacts, or for access to the network. Think before granting that access. Sandbox security is based on user input. Never click through any request for authorization without thinking.
    4. Starting with OS X 10.8.3, a third layer of protection has been added: a "Malware Removal Tool" (MRT). MRT runs automatically in the background when you update the OS. It checks for, and removes, malware that may have evaded the other protections via a Java exploit (see below.) MRT also runs when you install or update the Apple-supplied Java runtime (but not the Oracle runtime.) Like XProtect, MRT is effective against known threats, but not against unknown ones. It notifies you if it finds malware, but otherwise there's no user interface to MRT.
    5. The built-in security features of OS X reduce the risk of malware attack, but they are not, and never will be, complete protection. The best defense is always going to be your own intelligence. With the possible exception of Java exploits, all known malware circulating 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. The threat therefore amounts to a battle of wits between you and the scam artists. If you're smarter than they think you are, you'll win. That means, in practice, that you always stay within a safe harbor of computing practices. How do you know when you're leaving the safe harbor? Below are some warning signs of danger.
    Software from an untrustworthy source
    • Software of any kind is distributed via BitTorrent. or Usenet, or on a website that also distributes pirated music or movies.
    • Software with a corporate brand, such as Adobe Flash Player, doesn't come directly from the developer’s website. Do not trust an alert from any website to update Flash, your browser, or anything else.
    • Rogue websites such as Softonic and CNET Download distribute free applications that have been packaged in a superfluous "installer."
    • The software is advertised by means of spam or intrusive web ads.
    Software that is plainly illegal or does something illegal
    • High-priced commercial software such as Photoshop is "cracked" or "free."
    • An application helps you to infringe copyright, for instance by circumventing the copy protection on commercial software, or saving streamed media for reuse without permission.
    Conditional or unsolicited offers from strangers
    • A telephone caller or a web page tells you that you have a “virus” and offers to help you remove it. (Some reputable websites did legitimately warn visitors who were infected with the "DNSChanger" malware. That exception to this rule no longer applies.)
    • A web site offers free content such as video or music, but to use it you must install a “codec,” “plug-in,” "player," "downloader," "extractor," or “certificate” that comes from that same site, or an unknown one.
    • You win a prize in a contest you never entered.
    • Someone on a message board such as this one is eager to help you, but only if you download an application of his choosing.
    • A "FREE WI-FI !!!" network advertises itself in a public place such as an airport, but is not provided by the management.
    • Anything online that you would expect to pay for is "free."
    Unexpected events
    • You open what you think is a document and get an alert that it's "an application downloaded from the Internet." Click Cancel and delete the file. Even if you don't get the alert, you should still delete any file that isn't what you expected it to be.
    • An application does something you don't expect, such as asking for permission to access your contacts, your location, or the Internet for no obvious reason.
    • Software is attached to email that you didn't request, even if it comes (or seems to come) from someone you trust.
    I don't say that leaving the safe harbor just once will necessarily result in disaster, but making a habit of it will weaken your defenses against malware attack. Any of the above scenarios should, at the very least, make you uncomfortable.
    6. Java on the Web (not to be confused with JavaScript, to which it's not related, despite the similarity of the names) is a weak point in the security of any system. Java is, among other things, a platform for running complex applications in a web page, on the client. That was always a bad idea, and Java's developers have proven themselves incapable of implementing it without also creating a portal for malware to enter. Past Java exploits are the closest thing there has ever been to a Windows-style virus affecting OS X. Merely loading a page with malicious Java content could be harmful.
    Fortunately, client-side Java on the Web is obsolete and mostly extinct. Only a few outmoded sites still use it. Try to hasten the process of extinction by avoiding those sites, if you have a choice. Forget about playing games or other non-essential uses of Java.
    Java is not included in OS X 10.7 and later. Discrete Java installers are distributed by Apple and by Oracle (the developer of Java.) Don't use either one unless you need it. Most people don't. If Java is installed, disable itnot JavaScript—in your browsers.
    Regardless of version, experience has shown that Java on the Web can't be trusted. If you must use a Java applet for a task on a specific site, enable Java only for that site in Safari. Never enable Java for a public website that carries third-party advertising. Use it only on well-known, login-protected, secure websites without ads. In Safari 6 or later, you'll see a lock icon in the address bar with the abbreviation "https" when visiting a secure site.

    Stay within the safe harbor, and you’ll be as safe from malware as you can practically be. The rest of this comment concerns what you should not do to protect yourself.

    7. Never install any commercial "anti-virus" or "Internet security" products for the Mac, as they all do more harm than good, if they do any good at all. If you need to be able to detect Windows malware in your files, use one of the free security apps in the Mac App Store—nothing else.
    Why shouldn't you use commercial "anti-virus" products?
    • To recognize malware, the software depends on a database of known threats, which is always at least a day out of date. New threats are emerging on a daily basis. Research has shown that most successful attacks are "zero-day"—that is, previously unknown. Recognition-based malware scanners do not defend against such attacks.
    • Their design is predicated on the nonexistent threat that malware may be injected at any time, anywhere in the file system. Malware is downloaded from the network; it doesn't materialize from nowhere.
    • In order to meet that nonexistent threat, the software modifies or duplicates low-level functions of the operating system, which is a waste of resources and a common cause of instability, bugs, and poor performance.
    • By modifying the operating system, the software itself may create weaknesses that could be exploited by malware attackers.
    8. An anti-malware product from the App Store, such as "ClamXav," has the same drawback as the commercial suites of being always out of date, but it does not inject code into the operating system. That doesn't mean it's entirely harmless. It may report email messages that have "phishing" links in the body, or Windows malware in attachments, as infected files, and offer to delete or move them. Doing so will corrupt the Mail database. The messages should be deleted from within the Mail application.
    An anti-virus app is not needed, and cannot be relied upon, for protection against OS X malware. It's useful only for detecting Windows malware, and even for that use it's not really effective, because new Windows malware is emerging much faster than OS X malware. Windows malware can't harm you directly (unless, of course, you use Windows.) Just don't pass it on to anyone else.
    A Windows malware attachment in email is usually easy to recognize by the file name alone. An actual example:
    London Terror Moovie.avi [124 spaces] Checked By Norton Antivirus.exe
    You don't need any software to tell you that's a Windows trojan. Software may be able to tell you which trojan it is, but who cares? In practice, there's seldom a reason to use recognition software unless an institutional policy requires it. Windows malware is so widespread that you should assume it's in every unknown email attachment until proven otherwise. Nevertheless, ClamXav or a similar product from the App Store may be useful if an ill-informed network administrator says you must run some kind of "anti-virus" application.
    The ClamXav developer won't try to "upsell" you to a paid version of the product. Other developers may do that. Don't be upsold. For one thing, you should not pay to protect Windows users from the consequences of their choice of computing platform. For another, a paid upgrade from a free app will probably have all the disadvantages mentioned in section 7.
    9. It seems to be a common belief that the built-in Application Firewall acts as a barrier to infection, or prevents malware from functioning. It does neither. It blocks inbound connections to certain network services you're running, such as file sharing. It's disabled by default and you should leave it that way if you're behind a router on a private home or office network. Activate it only when you're on an untrusted network, for instance a public Wi-Fi hotspot, where you don't want to provide services. Disable any services you don't use in the Sharing preference pane. All are disabled by default.
    10. As a Mac user you don't have to live in fear that your computer may be infected every time you install software, read email, or visit a web page. But neither should you assume that you will always be safe from exploitation, no matter what you do. The greatest harm done by security software is precisely its selling point: it makes people feel safe. They may then feel safe enough to take risks from which the software doesn't protect them. "Hmmmm, this torrent is a crack of that new game I want. I think I'll download it. It could be a trojan, but the antivirus will warn me if it is." Then they wonder why their Mac is so slow all of a sudden. It's slow because it's running flat out mining Bitcoins for a hacker who has already sold their credit card number and banking passwords to a criminal gang. Maybe a week later the antivirus does warn them, but what good does that do?
    Nothing can lessen the need for safe computing practices.
  • Old Toad Level 10 (135,423 points)

    Anti virus software is not needed for Macs. They can slow down the Mac.   Check out this website for more info: The Safe Mac. It's an excellent source of information on the subject.




  • Ric Donato Level 4 (1,105 points)

    Hello aidan_s,

    Welcome to Mac. As Glenn suggested there are numerous AV programs for the Mac. Something to remember, coming from Windows there is less concern for virus, trojans, malware in general. That is not saying there is not Mac malware. Also, to monitor our systems Apple uses Gatekeeper. You can read about it in the following links:



    In addition to free ClamX AV, here are two possibly better programs Sophos, and Avast, both receive high ratings, yes both are free.


    Here is what I find strange, quote "…I do not want to buy a software that does this for me, but i just want to reassure my self that my $1300 investment is safe!…". Hum, you pay $1,300 for a wonderful laptop with the desire to keep it safe, yet you are adverse to spending less than .05% that cost for an anti malware program. Sorry, I do not get that logic.


    Any of the aforementioned free AV programs will serve your needs quite well. Hope that helps.





  • Old Toad Level 10 (135,423 points)

    More food for though from the author of The Safe Mac site and our resident virus/maleware expert:


    Mac anti-virus detection rates


    Mac anti-virus testing, part 2

  • DAVIDofmandalay Level 1 (0 points)

    Finally found where I tripped up: doing precisely a few days ago what you advised strongly against:

    "Do not trust an alert from any website to update Flash"


    Updated flash and now being told on all 3 browsers that all browser versions (including those I don't have even installed - Explorer - are old versions and need updating.


    It's preventing access to certain websites such as facebook and introducing lots of very unMac like behaviour onto the browser screens.


    Having been using mac since my first Powerbook 170, I never thought I'd see this on a mac platform.


    Any advice as to what the medicine is would be much appreciated.




    Software from an untrustworthy source

    • Software of any kind is distributed via BitTorrent. or Usenet, or on a website that also distributes pirated music or movies.
    • Software with a corporate brand, such as Adobe Flash Player, doesn't come directly from the developer’s website. Do not trust an alert from any website to update Flash, your browser, or anything else.
  • actionmarker Level 4 (1,555 points)

    The Safe Mac site that others have already mentioned, the author has recently posted an adware removal tool that you might find useful.


    Please note that it is Beta, so please backup first before using it. (I have personally tested it on my system will no ill effects)


  • Pantheria Level 1 (0 points)

    Several  Anti-Virus programs have been mentioned here. The two main ones Clam X and Avast.


    I am not familiar with Clam X but I did at one point after a scare download Avast.


      If you have limited band width I don't recommend it. My data more then doubled in the month I had it active. It cost me big time as I had gone over my limit.  I had downloaded it at the Library so the initial install wasn't the issue. Avast's updates were the issue. Plus, it slowed down my Mac Book Pro considerably.  Once I removed Avast my data usage and speeds returned to normal. 

  • Lisobelle Level 1 (0 points)


    I keep receiving this warning on my computer. It started about 2 weeks ago after I upgraded to Yosemite. This window pops up even when I'm not connected to the internet and when browsers are not even open. It interrupts me when doing anything from typing in word to watching a movie from a file on my computer. It won't let me do anything on my MacBook without clicking OK to dismiss it and then it pops up an hour later. It pops up right away when I restart my computer.

    Another forum told me the only way to fix it was to upgrade Java. This is something I tried initially, but it only made the issue worse.

    I did not know how useless it was when I upgraded it and I have uninstalled from my computer since. Now I have java blocked on all my web browsers with the exception of java script. I have my settings so that Java script is allowed, but all Java plug-ins are blocked. I am STILL getting this pop-up. Help me please!!

    Does anyone know how I can get rid of this? The only solution I have left is to wipe my computer and re-install everything. I do back up very regularly, so this isn't the most terrible thing. I am worried that I will re-install or put the issue back on my computer.

  • etresoft Level 7 (27,813 points)

    I suggest you start your own question. Otherwise it will just get lost here.

  • JinnyY Level 1 (0 points)

    This was a great read.  I have several Macs and they have been running slower and slower.  Tonight my MacBook Air audio stopped working and a little while later the screen saver changed to a very strange screen saver with the word "NEXT."  I am not sure what is happening, but it doesn't feel right.  I have been using Apple computers for a long time and I have never had an issue.  Last night my husband's Mac froze up with MacKeeper messages.  Apple removed the malware today.


    I would like to know how I can become more educated on security, beyond all the wonderful information you posted.  If you can provide any guidance to resources I could check out, it would be greatly appreciated.


    Thank you.

  • Kurt Lang Level 8 (36,670 points)

    The MacKeeper ads indicate you installed adware along with something else you recently intentionally installed. This kind of garbage has become rampant. Especially at C|NET's and . Avoid these software aggregate sites like the plagues they have become.

  • Miracles46 Level 1 (0 points) too! I have that same problem..... ugh. And my computer is acting like I have a virus.

  • David Cun Level 4 (1,405 points)

    I urge Aidan and all others to read and digest Link’s extremely informative post; especially 5, 6, and 10.  I’d like to name a culprit or two; like Mackeeper, the most ubiquitous one out there today.  Never respond to any popup etc that says stuff like, “We’ve found problems with your computer!  Download_________now”  or “Download__________to speed up your computer.” etc.  Funny, but I never get the Mackeeper thing on Safari, but quite a bit on Firefox.


    The FlashPlayer popup CAN come from Adobe.  Personally, I ignore that probably safe popup and instead close my Browser, open Flash Player and check for updates.  What Link suggests is that if the popup comes from a website, ignore it.  Sometimes I even close the browser to get rid of a popup; make sure I don’t do anything even accidentally.  Point being, just be careful what you download, even email attachments.  If you’re careful/mindful you will not get any viruses, malware, adware, trojan horses.  OS X even gives you a warning when you try to open/install an app!  When that warning comes up, think before acting and then trash that app unless you’re very sure you want to install it.


    Like Link says, most bad actors are “zero day”.  So, even ClamXav is behind the eight ball.  I’ve had ClamX for a couple years but just recently I trash it too. 


    I’ve been a Macster for years (since OS 7 and DOS).  I’ve never gotten a virus.  Sure, I’ve downloaded suspicious stuff (like .exe files from emails).  Just be careful what you actually install on your Mac.


    Aidan, no you don’t need any software to check for bad stuff (malicious software).   Go through all your apps and utilities and check for yourself for anything you don’t recognize or want.  Come back here and open another thread if you find something you’re suspicious about.


    Enjoy your Mac!

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