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virus protection for my macbook pro

4062 Views 22 Replies Latest reply: Mar 19, 2013 2:56 AM by thomas_r. RSS
  • Linc Davis Level 10 Level 10 (108,135 points)
    Currently Being Moderated
    Mar 18, 2013 2:36 PM (in response to Steven.m089)

    1. 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 intruder 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.
      
    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, but internally Apple calls it "XProtect." The malware recognition database is automatically checked for updates once a day; 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.
    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 actually been tested by Apple (unless it comes from the Mac App Store), 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. For most practical purposes, applications recognized by Gatekeeper as signed can be considered safe.
        
    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 find some other way to evade Apple's controls.         
    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 presumably effective against known attacks, but maybe not against unknown attacks. It notifies you if it finds malware, but otherwise there's no user interface to MRT.
     
    5. Beyond XProtect, Gatekeeper, and MRT, there’s no evidence of any benefit from other automated protection against malware. The first and best line of defense is always 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 malware attacker. If you're smarter than he thinks you are, you'll win.
        
    That means, in practice, that you never use software that comes from an untrustworthy source. How do you know whether a source is trustworthy?
    • Any website that prompts you to install a “codec,” “plug-in,” "player," "extractor," or “certificate” that comes from that same site, or an unknown one, is untrustworthy.
    • 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 visitors who were infected with the "DNSChanger" malware. That exception to this rule no longer applies.)
    • Pirated copies or "cracks" of commercial software, no matter where they come from, are unsafe.
    • Software of any kind downloaded from a BitTorrent or from a Usenet binary newsgroup is unsafe.
    • Software with a corporate brand, such as Adobe Flash Player, must be downloaded directly from the developer’s website. If it comes from any other source, it's unsafe.
    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, Java on the Web is 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 it — not JavaScript — in your browsers. In Safari, this is done by unchecking the box marked Enable Java in the Security tab of the preferences dialog.
       
    Regardless of version, experience has shown that Java on the Web can't be trusted. If you must use a Java applet for a specific task, enable Java only when needed for the task and disable it immediately when done. Close all other browser windows and tabs, and don't visit any other sites while Java is active. Never enable Java on a public web page that carries third-party advertising. Use it, when necessary, 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.

    Follow the above guidelines, 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 from malware.

    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 the free software ClamXav — nothing else.
      
    Why shouldn't you use commercial "anti-virus" products?
    • 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. ClamXav doesn't have these drawbacks. That doesn't mean it's entirely safe. 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.
        
    ClamXav is not needed, and should not be relied upon, for protection against OS X malware. It's useful only for detecting Windows 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. The file name will often be targeted at people who aren't very bright; for example:
      
    ♥♥♥♥♥♥♥♥♥♥♥♥♥♥!!!!!!!H0TBABEZ4U!!!!!!!.AVI♥♥♥♥♥♥♥♥♥♥♥♥♥♥.exe
       
    ClamXav may be able to tell you which particular virus or trojan it is, but do you care? In practice, there's seldom a reason to use ClamXav unless a network administrator requires you to run an anti-virus application.
        
    9. The greatest harm done by security software, in my opinion, is in its effect on human behavior. It does little or nothing to protect people from emerging threats, but they get a false sense of security from it, and then they may behave in ways that expose them to higher risk. Nothing can lessen the need for safe computing practices.
      
    10. 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.

  • Linc Davis Level 10 Level 10 (108,135 points)
    Currently Being Moderated
    Mar 18, 2013 3:43 PM (in response to Linc Davis)

    Avast prevents System Update from working:

     

    The operation couldn’t be...: Apple Support Communities

  • thomas_r. Level 7 Level 7 (27,050 points)
    Currently Being Moderated
    Mar 18, 2013 4:28 PM (in response to Linc Davis)

    Linc, you of all people should know the hazards of taking a few scattered reports here too seriously. Especially given the poor quality of information. The first link you posted involved someone who had both Avast and Kaspersky installed, and who continued to have problems after Avast was removed. In the third, you simply posted your opinion, which was never confirmed or denied by the OP. In the fourth one, the OP removed more than one program at once, so the culprit is not known.

     

    This is not quality data. I'm actually disappointed that you would resort to such.

     

    As for your snide remarks about my memory, I would like to draw your attention to the date on those comments of mine that you refer to. At that time, I was commenting based on a handful of scattered reports here. Since that time, I have performed not one but two tests of Mac anti-virus software that included Avast. I now restrict my comments on Avast to what I know, rather than what I think I know.

  • Linc Davis Level 10 Level 10 (108,135 points)
    Currently Being Moderated
    Mar 18, 2013 6:17 PM (in response to thomas_r.)

    No, Thomas. I've tried at least once that I can recall to explain to you how to read a kernel panic. I'm not going to repeat the exercise.

  • SwankPeRFection Level 4 Level 4 (1,435 points)
    Currently Being Moderated
    Mar 18, 2013 6:44 PM (in response to Linc Davis)

    How do you explain how the rest of us who run programs you don't seem to trust don't experience any kernel panics or other "known" issues as you put them.  Let me take a stab at it... are you going to use that line "you think you don't have any problem, but you actually do"? :rolleyes:

  • thomas_r. Level 7 Level 7 (27,050 points)
    Currently Being Moderated
    Mar 18, 2013 7:36 PM (in response to Linc Davis)

    No, you've never tried to explain anything to me in that regard. You have told me I don't know how, and criticized me for it. That's what you do - you tell people things, and if they disagree with you, they are simply wrong.

     

    In this case, it does not take amazing talents at reading kernel panic logs to tell that your data is sparse and not even remotely conclusive. But at this point, I think we should simply leave it to the reader to decide whether to trust someone who has done some testing with the product in question or someone who has never even used it.

  • SwankPeRFection Level 4 Level 4 (1,435 points)
    Currently Being Moderated
    Mar 18, 2013 9:28 PM (in response to thomas_r.)

    Thomas, here's a thread that shows the expertise that's needed to properly read a Kernel Panic and suggest a fix.  https://discussions.apple.com/thread/4897194?tstart=120

     

    Obviously I'm being facetious with this, but you get the idea.  There's no magic to it.  Usually something within the dump points to the issue app or system component that could have caused it.  Generally speaking it's the first one listed.  Take care of that one and test again.  If it dumps again, you see what module and/or app is indicated next.  It's not that hard to do really.  If a graphic designer can do you, so can you.

     

     

    Sorry for the hijack of this thread to show you this, wish this site had some PM options, but it doesn't seem to.

  • thomas_r. Level 7 Level 7 (27,050 points)
    Currently Being Moderated
    Mar 19, 2013 2:56 AM (in response to SwankPeRFection)

    I actually know how to read a kernel panic log just fine... Just not up to Linc's standards, as he has repeatedly told me.

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