12 Replies Latest reply: Jul 8, 2013 1:31 AM by Tallberg
Tallberg Level 1 Level 1 (0 points)

I'm getting conflicting advice!

 

Do I need anti virus software?

 

Would it be advisable to activate the firewall already installed on the Mac?  If so, will the computer be slowed down?

 

Very confused!


iMac (21.5-inch, Late 2012), OS X Mountain Lion (10.8.4)
  • 1. Re: Do I need virus software  to protect my i-Mac?
    RJB321 Level 1 Level 1 (5 points)

    No, you dont need antivirus, macs dont get PC viruses. But, if you're worried about computer safety, then go ahead and turn the firewall on.

  • 2. Re: Do I need virus software  to protect my i-Mac?
    jayv. Level 4 Level 4 (1,230 points)

    Personally, i think antivirus software can't hurt. Great free AV applications are available like Sophos and Avast. Even if it doesn't find anything, it's good for piece of mind (and it will most likely find some PC viruses but they won't affect your Mac).

     

    RJB321 is unfortunatly misinformed. Macs do 'get PC viruses'. My antivirus catches a few every week that are attached to spam emails. While they do not affect my Mac, i do get them on my system. While the risk of infection is low compared to Windows users, the risk is there and has been there for a very long time. Mac malware (malicious software) exists and is on the rise as Mac popularity and market share grows.

     

    I do recommend enabling OS X's firewall. It's integration into the system is very good and it will not affect your system's performance, at all.

     

    Here are some links that may help you:

    OS X Built-in security (by Moi)

    Antivirus for Mac (by Moi)

    Antivirus detection rates (goes to show there was/is plenty of malware out there for Mac)
    There are no Mac viruses (by Thomas Reed)

    Short history of Mac malware (by Sophos, also currently my preferred antivirus)

    Antivirus, just one piece of a big puzzle (by Moi)

  • 3. Re: Do I need virus software  to protect my i-Mac?
    RJB321 Level 1 Level 1 (5 points)

    Spam emails are different. The software blocks viruses, but if you sign up for bad things and get spam emails, that's your fault.

  • 4. Re: Do I need virus software  to protect my i-Mac?
    jayv. Level 4 Level 4 (1,230 points)

    So you can only get spam if you sign up for bad things? There are no companies out there selling email databases to eachother, bots crawling the net looking for email addresses on forums and websites, companies that are hacked and have their email database stolen? Just to name a few.

  • 5. Re: Do I need virus software  to protect my i-Mac?
    RJB321 Level 1 Level 1 (5 points)

    I'm just saying, some of those spam emails are probably on you.

  • 6. Re: Do I need virus software  to protect my i-Mac?
    jayv. Level 4 Level 4 (1,230 points)

    Sorry RJB321, you are not making sense. Spam or not, email can contain malware. Signing up for 'bad things', while generally not a good idea, has nothing to do with whether or not your Mac can get infected. There is more malware being delivered by legit trusted websites than **** or illegal download sites. You can look up the Google publication if you want.

     

    I don't know if your opinion comes from hear-say or if you have facts to back them up but i suggest you do some research before giving others wrong advice. There's nothing wrong with not knowing as long as you are willing to learn and can accept being proven wrong.

  • 7. Re: Do I need virus software  to protect my i-Mac?
    PurpleKrayon Level 1 Level 1 (0 points)

    I agree with you Jay, the world where only one percent of the world used macs and there are no viruses for them is in the past. This is now a common misconception.

  • 8. Re: Do I need virus software  to protect my i-Mac?
    Linc Davis Level 10 Level 10 (118,235 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 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. 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 a false sense of safety. 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.

  • 9. Re: Do I need virus software  to protect my i-Mac?
    MadMacs0 Level 4 Level 4 (3,735 points)

    Tallberg wrote:

     

    Would it be advisable to activate the firewall already installed on the Mac?  If so, will the computer be slowed down?

    Slightly slows down your internet access. The firewall on your computer is almost always redundant to the one in place on the router managing your local network. If this is a trusted network that uses a strong WPA2 password, then you don't need to turn yours on. See Do I need a firewall?.

     

    You can check your setup at Shield Check or GRC's ShieldsUp.

  • 10. Re: Do I need virus software  to protect my i-Mac?
    Tallberg Level 1 Level 1 (0 points)

    Thank you for all of your advise.

  • 11. Re: Do I need virus software  to protect my i-Mac?
    Tallberg Level 1 Level 1 (0 points)

    Thanks for your advice.

     

    I appreciate your candour.

  • 12. Re: Do I need virus software  to protect my i-Mac?
    Tallberg Level 1 Level 1 (0 points)

    Thanks for you help and simpe suggestions.