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OK, look. Semantic debates aside, there are two general types of malware you need to wary of:

1. The kind that can sneak into your system without your knowledge, and without your intervention. This kind is dangerous because you don't know how it showed up, or what you might have done to get it there. This is the kind of virus that could infect your computer simply by having it turned on. The only way to detect this kind of virus is with a virus scanner that is continually, actively, checking your computer, and/or to block open ports or vulnerabilities that these viruses take advantage of (e.g. use a firewall).

2. The kind that you allowed into your computer, by opening an application, clicking on a link, installing a program, etc. On a Mac, you often have to type your password in to allow installation of any software that affects system services. If one of these shows up on your computer, it is guaranteed to be traced back to some action that YOU performed.

EVERY PLATFORM has variations of number 2. There is simply no way around that.However, on a Mac, they are extremely rare because, as the thread above indicates, the only places they have been seen "in the wild" are on porn sites and in pirated torrents. Avoid those two things, and exercise common sense when people send you attachments that seem fishy, and you're good to go. Even Facebook can be a vector for this sort of attack (if your friends are all suddenly joining groups with names like "YOU WON'T BELIEVE WHAT SHE DID WHEN SHE SAW THIS VIDEO!" -- don't click it. I bet it tries to install something that propagates itself further around Facebook.)

OS X has NO current instances of number 1. A continuous-scanning virus checker is not necessary unless you think there is a chance you will be tricked into allowing a trojan/worm/malware (number 2) into your computer. But again, with common sense and vigilance, you should be just fine.
 
OK, look. Semantic debates aside, there are two types of viruses you need to wary of:

1. The kind that can sneak into your system without your knowledge, and without your intervention. This kind is dangerous because you don't know how it showed up, or what you might have done to get it there. The only way to detect this kind of virus is with a virus scanner that is continually, actively, checking your computer. (climbing down the chimney or through a window without you knowing)

2. The kind that you allowed into your computer, by opening an application, clicking on a link, installing a program, etc. On a Mac, you often have to type your password in to allow installation of any software that affects system services. (knocking on the door, disguised as a Girl Scout selling cookies, waiting for you to open the door and invite them in)

EVERY PLATFORM has variations of number 2. There is simply no way around that. However, on a Mac, they are extremely rare because, as the thread above indicates, the only places they have been seen "in the wild" are on porn sites and in pirated torrents. Avoid those two things, and exercise common sense when people send you attachments that seem fishy, and you're good to go.

OS X has NO current instances of number 1. A continuous-scanning virus checker is not necessary unless you think there is a chance you will be tricked into allowing a trojan/worm/malware (number 2) into your computer. But again, with common sense and vigilance, you should be just fine.
Well said! (my notes in blue) And don't get all your anti-virus advice from companies like Sophos that only want to scare you into buying their anti-virus apps!
 
I find that many individuals using Windows XP admin accounts do not understand the difference between a Trojan and a Virus. The Windows XP admin account has superuser (similar to root) privileges without authentication so a Trojan that can cause extensive damage can be installed simply by accessing a file (email, document, video, etc.)

I refer to Windows XP because it is still the most used Windows OS; this is mitigated somewhat in Vista and 7 via UAC. You should still have a unique identifier (password) attached to authentication mechanism. So, Windows users should run as standard users. Using a standard account in Windows causes issues with some software, such as some online games, that require admin accounts (or "run as administrator"; superuser) to function. This example, using online games, shows the problem with how software is being written for Windows. This problem lead to DLL hijacking exploit.

On Mac OS X, the admin account requires authentication with a password to elevate privileges. Trojans that can be installed without authentication in OS X admin accounts, such as OSX/Leap-a, are not able to cause a lot of damage (can not install rootkits = kexts). This is why such threats are fewer in OSX. Running as a standard user in Mac OS X allows ineffective malware, such as Leap-a, to cause even less damage. For example, Leap-a in admin account effected apps that belong to admin group but not system (system = default Mac OS X apps; Safari, Mail, etc) and even fewer apps in a standard account. (EDIT: Leap-a was an Input Manager. As of Leopard, Input Managers require Admin password to install; in 10.6, Input Managers also do not function with 64 bit apps. In Tiger, Leap-a required authentication via Admin password to infect iChat to spread via Bonjour.)

The issue with online games found in Windows is not problematic on Mac OS X given that software for Mac is written following the guidelines of the principles of least privilege more so than Windows software. Here is a quote from that Wiki concerning Windows standard accounts:
For example, Microsoft states “Running in standard user mode gives customers increased protection against inadvertent system-level damage caused by "shatter attacks" and malware, such as root kits, spyware, and undetectable viruses”
 
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so then explain this one you guys can- i get my new mac, very nice and super fast- it really is a piece of lightning. 6months down the line i notice that the mac has slowed down so damn much. so after clearing cookies and erasing the free space and lots of other stuff people had asked- its still damn slow. and i still have over 150gb still left free on the hdd.

is this a trojan or a virus? or neither?

p.s. when i got my new mac i restored from time machine so the new unit pretty much had all the other stuff on it, but in a new box!
 
so then explain this one you guys can- i get my new mac, very nice and super fast- it really is a piece of lightning. 6months down the line i notice that the mac has slowed down so damn much. so after clearing cookies and erasing the free space and lots of other stuff people had asked- its still damn slow. and i still have over 150gb still left free on the hdd.

is this a trojan or a virus? or neither?

p.s. when i got my new mac i restored from time machine so the new unit pretty much had all the other stuff on it, but in a new box!

Whole machine slow or just the browser?

If you want peace of mind, download an AV scanner of your preference and run an on-demand scan to check you system. Post a screen shot if it finds anything. Afterward, uninstall the AV if you wish.
 
Word Macro Virus

On our home network of Macs, we've had documents infected with Word macro virus (W95?). The documents came from the kid's school digital lockers. There may be some discussion as to whether these are really Mac malware, as they don't do anything to a Mac. But you could be a vector. Every once in awhile I point Norton to run on these iMacs, and it cleans them up.
 
whole machine

If it is not malware causing the problem (most likely is not), you may have a problem that requires a clean install.

Before doing a clean install, go to /Applications/Utilities/ and launch "Console," which is a real-time log viewer, to see if you have any error messages. Post a screen shot if you find errors. Instructions on how to take screen shots are found in this forum.
 
It's funny reading through this thread. So either we have no viruses, one virus, or at most a few. So what? Look what the Windows world has to put up with. I do use Windows 7, with virus protection, and it's not at all bad.

That being said, not worrying about viruses for OS X is an added bonus for being a Mac user. But what I like, even though Windows 7 is great, is that OS X is pretty intuitive.

Even if the Mac had viruses, and lots of them, I would simply get anti-virus software and use OS X 4 times out of 5 and only use the PC for certain tasks.
 
6months down the line i notice that the mac has slowed down...

...is this a trojan or a virus? or neither?
Neither. There are a great number of things that could slow your system down. Malware is the very last possibility.
On our home network of Macs, we've had documents infected with Word macro virus (W95?)..
It must have been quite some time ago, unless you're running outdated software. Until a couple months ago, that isn't possible, since Office 2008 didn't support macros at all. They just re-introduced macros with Office 2011.
 
Even though GGJstudios as continuously stated that a virus is self executing, its incredible that people keep coming back with "Viruses" that have been found through something they clicked on and opened. :confused:

People believe what they want to believe i guess.

I believe GGJstudios. :cool:
 
so then explain this one you guys can- i get my new mac, very nice and super fast- it really is a piece of lightning. 6months down the line i notice that the mac has slowed down so damn much. so after clearing cookies and erasing the free space and lots of other stuff people had asked- its still damn slow. and i still have over 150gb still left free on the hdd.

So after all this time in this thread, it turns out that you just didn't ask the right question from the start. You asked "Has anybody ever had a virus on their Mac", but your question is really "why is my Macintosh slower than it used to be". Something completely unrelated.

Open "Activity Monitor". Turn on "All Processes", click on "CPU". See what is using CPU time on your Macintosh. Then click on "System Memory". Check how much memory is "used". Check what it says under "Page Ins" and "Page Outs". Tell us what you find.
 
It's funny reading through this thread. So either we have no viruses, one virus, or at most a few. So what? Look what the Windows world has to put up with. I do use Windows 7, with virus protection, and it's not at all bad.

This is true. I can give you two stories from my own recent experience that illustrates how much more prevalent Windows viruses and malware are.

1. Last year I had a netbook running XP. I chose not to install any kind of antivirus software on it because I figured, like I do on my Mac, hey, as long as I'm smart and don't download stupid things or click on stupid links, I should be fine. One month later, my ISP shut down my internet connection. When I called them to ask why, they said one of my computers was infected with a virus and was attempting a cyber-attack. I downloaded some AV software and scanned my netbook and, sure enough, there was a virus. I have no idea where it came from. From that point on I made sure to run AV software on it constantly. But that slowed down the machine significantly. I eventually sold the netbook when I bought my iPad.

2. Also last year, I was one of several people lined up to do a presentation at a local church. I gave my USB stick, with my presentation on it, to their tech operator so they could copy my files. Later when I put the stick back into my Mac, I noticed a file that hadn't been there before. It had a ".vbs" extension (VBscript). Someone had a computer infected with a VBscript worm/virus, and that infected the church computer and probably every USB stick that had touched that computer that morning. If I had inserted my stick into a PC, it would have become infected too. Since the Mac is immune to that sort of virus, I simply deleted the .vbs file and sent an email to the church warning them of what I found.

Meanwhile, I have been using OS X since 2003 and I have been absolutely malware free in all that time.
 
That's a trojan, not a virus. You only get it if you download and install video codecs from porn sites. :rolleyes:

Mostly true. Another more common way to get a trojan is from other computers/drives. While you may not have gone to a dodgy site, someone else may have and the trojan can spread accross drives or other files.

By the time you find out its affected one computer in could have been passed around many other computers. This is why its still worth having an anti virus/trojan/malware/spyware program on any computer.

I have used Virus barrier X for years with no slow downs or any other problems.
 
Mostly true. Another more common way to get a trojan is from other computers/drives. While you may not have gone to a dodgy site, someone else may have and the trojan can spread accross drives or other files.

By the time you find out its affected one computer in could have been passed around many other computers.
Not true! You really need to get some facts straight before you post misinformation. Trojans do NOT "spread across drives". You have to manually activate a trojan. The trojan described is ONLY found by downloading and installing software from dodgy sites.

Why do you continually post false information? Don't you get it? If you want to run anti-virus on your Mac, go ahead. But STOP misleading people by posting things that aren't true!
 
Ive always read once a trojan has been downloaded and activated it can spread across drives.
 
Ive always read once a trojan has been downloaded and activated it can spread across drives.

That's a virus. Trojans are not self-replicating. Just because you read something, doesn't make it true. You need to check your sources.
 
I love to watch GGJstudios do his thing in these "virus" threads

Give it up guys, he's done his research and knows what he's talking about. I'm beginning to think that he's read every internet article ever written on Mac Malware and committed it to memory.
 
I love to watch GGJstudios do his thing in these "virus" threads

Give it up guys, he's done his research and knows what he's talking about. I'm beginning to think that he's read every internet article ever written on Mac Malware and committed it to memory.

:D I was thinking the same.
 
I love to watch GGJstudios do his thing in these "virus" threads

Give it up guys, he's done his research and knows what he's talking about. I'm beginning to think that he's read every internet article ever written on Mac Malware and committed it to memory.

My memory isn't that good! But I have done a LOT of research on the topic. These threads would be much shorter if some others would do the same. I wouldn't have to spend so much time refuting erroneous statements.
 
So after all this time in this thread, it turns out that you just didn't ask the right question from the start. You asked "Has anybody ever had a virus on their Mac", but your question is really "why is my Macintosh slower than it used to be". Something completely unrelated.

Open "Activity Monitor". Turn on "All Processes", click on "CPU". See what is using CPU time on your Macintosh. Then click on "System Memory". Check how much memory is "used". Check what it says under "Page Ins" and "Page Outs". Tell us what you find.

no, i did ask the right question from the beginning, this was just another side question that arose when reading all the post's back from people. i did what you said and there seems to be no harsh usage of cpu or memory at all
 
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