6 Replies Latest reply: Sep 1, 2013 5:03 AM by michaelsip4
jerry_newappleuser Level 1 (0 points)

should i run malwyrbytes or spybot to check for viruses or spy ware on my imac os x?

iMac, OS X Mountain Lion (10.8.4)
  • Linc Davis Level 10 (184,790 points)

    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.
    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, 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 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.
    For the reasons given above, App Store products, and 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. OS X 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 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. XProtect, Gatekeeper, and MRT reduce the risk of malware attack, but they're not absolute protection. 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, or that does something inherently untrustworthy. How do you know what 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 that purports to help you do something that's illegal or that infringes copyright, such as saving streamed audio or video for reuse without permission, is unsafe. All YouTube "downloaders" are in this category, though not all are necessarily harmful.
    • 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.
    • Even signed applications, no matter what the source, should not be trusted if they do something unexpected, such as asking for permission to access your contacts, your location, or the Internet for no obvious reason.
    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.

    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. Any database of known threats is always going to be out of date. Most of the danger is from unknown threats. If you need to be able to detect Windows malware in your files, use one of the free anti-virus products in the Mac App Store — 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. An anti-malware product from the App Store, such as "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.
    An anti-virus app 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:
    Anti-virus software 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 the software unless a network administrator requires you to do it.
    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 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 is going to be infected every time you install an application, read email, or visit a web page. But neither should you have the false idea that you will always be safe, 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. Nothing can lessen the need for safe computing practices.

  • Topher Kessler Level 6 (9,865 points)

    I wouldn't. My recommendation for anyone who has a concerns about malware is to get a reputable and lightweight (preferibly free) malware scanner such as Sophos Home Edition, and use that to periodically scan the system for malware. This software should not adversely affect your system (though there is always a potential that any software addition to the system can case issues), and I have installed it on many systems with no problems that I've seen.

  • MadMacs0 Level 5 (4,700 points)

    jerry_newappleuser wrote:


    should i run malwyrbytes or spybot to check for viruses or spy ware on my imac os x?

    Are you running Windows on your Mac?


    Malwarebytes does not run on OS X. Here's what they have said about that.


    There is no Spybot for OS X. Note what they say about that here. Most Mac A-V software doesn't check for it either since Spyware generally requires physcial access to your computer or shared access that you would have to approve over the network.

  • R C-R Level 6 (17,375 points)

    Topher Kessler wrote:

    I wouldn't. My recommendation for anyone who has a concerns about malware is to get a reputable and lightweight (preferibly free) malware scanner such as Sophos Home Edition, and use that to periodically scan the system for malware.

    I suggest that if you decide to use Sophos, use the recommended (default) settings. This enables the "on access" scanner, which automatically scans files before they are opened, in the background. This is a very "lightweight" process, using negligible system resources & taking only a tiny fraction of a second to complete.


    I have been using Sophos Home Edition since it was first released, on several different Macs running several different OS versions. I have never had any problems with it whatsoever.

  • R C-R Level 6 (17,375 points)

    Linc Davis wrote:

    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. Any database of known threats is always going to be out of date. Most of the danger is from unknown threats. If you need to be able to detect Windows malware in your files, use one of the free anti-virus products in the Mac App Store — nothing else.

    Linc is entitled to his opinion but I suggest taking any such overly broad statements as "they all do more harm than good" with a very large grain of salt. To begin with, how could this be anything but speculation unless he (or anyone else making the same claim) has tried all the available commercial products, examined their code, & discovered some weakness in the processes they run?


    And while it is true the databases are always going to be out of date, it is not true that most of the danger is from "unknown threats," which are most often referred to as "zero day attacks." The likelihood of a typical Mac user encountering one of these attacks is vanishingly low. That is because their value lies in their remaining undiscovered by the security community & releasing them "into the wild" would destroy that value. For this reason they are almost exclusively used to selectively attack very high value targets like financial institutions, companies with lucrative trade secrets to protect, & sometimes even governments.


    They, & the vulnerabilities they exploit, are closely guarded secrets, revealed if at all only to a select few willing to pay large sums for them and trusted not to use them so indiscriminately that they would be discovered. When they are discovered, for instance by security firms (some of which employ people posing as criminals willing to buy them) or by other criminal hackers who package them into "crime kits" to sell to still other criminals, "zero day" has passed.


    This is the time of the greatest danger to typical users: the secret is out, the attacks are "in the wild," & it becomes a race for Apple & all the other security software providers to implement & distribute counter-measures before typical users encounter them. Betting on Apple alone to do this in a timely manner is good; but betting on Apple plus a commercial security outfit with a good track record is better.


    It is really pretty simple: since it is a race, the faster you get an effective counter-measure running on your system the better protected you are. Among other things, that means getting database updates ASAP from whomever provides them & making sure they are applied to the widest possible variety of software that you might encounter, whatever the source.

  • michaelsip4 Level 2 (300 points)

    Jerry, having crossed over from the windows world as well.... I have noticed you have "solid feed back here"

    as for myself  I have noted that at times there are apple purists (stay with apple based products and software and you are safe - claimxav av for windows cross over and your fine).. There are other people that are cross over based (win/mac) which look at everything from those perspectives focusing on mac and the win relationship (cause and effect),  You also have the ability to run windows on a mac from bootcamp or a virtual configuration.


    please see the following link(s)   http://www.thesafemac.com/tech-guides/

    http://www.thesafemac.com   to give yourself a little more of a foundation.