[reemas]

how do you get a virus on a mac? in what form do they come? applications? word files?

i wanted to know if there were certain things i should avoid downloading from the web or wherever.

i know on pc's they can come as .exe files or word macros, etc.

thanks.

[ManOfSteal]

In general, you don't get viruses on Macs and if you do, they are normally in the form of a "macro" virus that is carried in applications (namely the M$ Office suite...go figure) and are harmless, but annoying until remedied.

With that said, your Mac can obtain and spread a virus sent by a PC through e-mail or something; however, it just won't affect your Mac like it will affect Windows based machines...

[Brass]

Just to clarify a bit on the previous post...

There are currently NO known Mac OS X viruses.

There are the MS Office macro-viruses, but no operating system Mac OS X viruses as such.

However, there surely will be one day, so it doesn't hurt to take the same precautions on the Mac as you would on the Wintel PC. Of course any windows-specific virus will not do anything on the Mac (eg, .exe files).

[TETENAL]

"Spread" is misleading. There is no Mac virus yet. You can intentionally send a virus by mail if you add it as an attachment so that it is mailed like any other file would be. But it is not spreading by it self, nor can it be forwarded accidently.

The only thing that currently can affect you on Mac are Microsoft Office macro viruses. Some of those might work on Mac since they are using a scripting language. If you turn off the macro feature in Office you are safe.

Some safety guidlines:

• Don't download and run programs from untrusted sources. Trojans (or more general programs that don't behave as you wish they should) exist on every platform.
• Don't klick on stupid mail attachments.

You can run an anti-virus program with regularly updated virus definitions (I wrote that for Millennium). If you read Mac news regularly you can as well delay using such a program until the first Mac virus is discovered.

[turtle777]

Originally posted by TETENAL:
If you read Mac news regularly you can as well delay using such a program until the first Mac virus is discovered.

If he READ Mac news regularly, he would not have asked the question !

-t

[Millennium]

No viruses are known to exist for the Mac yet. However, it would be wise not to believe that Macs are invincible.

There are three kinds of programs (malware, in this case) which we need to discuss here: viruses, Trojan horses, and worms. All of these programs do Bad Things. The difference is in how they spread.

A virus (plural viruses) is a small snippet of code living inside a file. Viruses spread by copying themselves into other files on the same machine. Theoretically a virus can infect any file, but they usually restrict themselves to actual applications, since the code has to run before it can spread. Because they spread from file to file, they have no way of moving between machines on their own; someone must copy an infected file over in order for the virus to spread. Viruses are the hardest type of malware to detect and remove, since they can infect any file on the machine. Fortunately, however, they are also the least common kind of malware in this day and age, because they are extremely difficult to write properly.

A worm is a small program which tries to copy itself from machine to machine. Unlike a virus, it cannot hide inside other files, which makes it easier to detect and remove. However, it doesn't need to hide inside files to spread, because it has mechanisms for going directly from machine to machine, which a virus can't do. Most of the e-mail "viruses" of the past few years are actually worms. Worms tend to spread much more quickly than viruses because they go directly between machines, but they also tend to die out much more quickly because they're easier to detect and remove.

A Trojan horse is just a program that does something other than what it claims to do. It may even do what it claims, and simply do something else on the side. Unlike viruses and worms, Trojan horses have no ability to spread on their own; all of the legwork must be done by people. Therefore, they don't usually show up in "outbreaks"; more often they're written to attack a specific person. Many forms of spyware and adware, such as the infamous Bonzi Buddy, could be considered as Trojan horses, because they don't tell the user everything that they're doing. Software which installs spyware could also fall under this category if they're not forthright about it.

Ahem. For now, there is only one way for a theoretical virus to enter a Mac: through running an application. Many of the worst Windows security problems, such as ActiveX, do not exist on the Mac, and so viruses cannot enter on these channels. In particular, a worm cannot enter your Mac through a Web page or e-mail message.

Word macro viruses will affect Macs, but otherwise Macs are completely immune to Windows viruses (the rverse is also true). You can still download a file containing a virus, but the virus itself will not be able to run, and so you cannot become infected. If you give that file to a Windows user, however, then that person could become infected. This is why it's still a good idea to run anti-virus software on the Mac.

Trojan horses exist for the Mac, but they are not widespread. Only one spyware program is known to have ever been written for the Mac, and that program is no longer being distributed even by its makers.

[spork]

Hello friends and gurus.

12" 133 g4 pbook user here.
two days ago, I downloaded an arquive from limewire called install office from internet or something like that. downloaded dmg and it opened an icon on the desktop. right button click to see inside folder and immediately everthing on the desktop vanished. computer began to act weird. closed everything and shut down. on restart, desktop was as if it just came from box. hd still had my icon and name and I existed as main and only user and my programs were still all installed in aplications, but no more public folder and no more files of mine. 30 gb of music and files vanished. norton unerase recovered about 20000 files, but about 60 or so were usable. the rest 0kb.
any ideas about what happened.
I had office installed just to use word and am now trying neooffice .

any ideas greatly appreciated.
all the best in 2005

12" 133 g4 pbook
g4 533 dual

[cpac]

This was a known trojan (see above)- it deleted your home folder.

If you already had Office installed, why were you trying to download a copy from limewire? (and why did you think such a small file would be Office and/or that M$ allowed to people to "install from the internet"??)

The first malicious Trojan for Mac OS X has been found in the wild, leading some to claim the platform may be on the verge of increased attention from virus writers.

The Trojan—dubbed AS.MW2004.Trojan by anti-virus company Intego—was first discovered by a reader of British Mac magazine MacWorld. It takes the form of a file purporting to be a version of the newly released Office 2004 for Mac and is available on download services such as LimeWire.

However, despite appearing with a legitimate-looking icon, the Trojan is in fact a simple AppleScript application that, when run, erases the contents of the user's Home folder. And, unlike the real release of Office 2004, the application is only 108KB in size.

[Laurence]

[quote]any ideas about what happened. [\quote]

I'll take a guess...

It sounds like someone wrote a program to delete your home directory and then they named it "Office Installer". They then gave it a custom icon that looked like a folder and then shared it using the Gnutella network thinking how hilarious it would be when someone downloaded it and it deleted all their files.

This is not a virus, but in the future, I would recommend creating a non-admin user account on your computer and use it when you are downloading warez from an unknown source.

[Millennium]

Originally posted by spork:
12" 133 g4 pbook user here.
two days ago, I downloaded an arquive from limewire called install office from internet or something like that. downloaded dmg and it opened an icon on the desktop. right button click to see inside folder and immediately everthing on the desktop vanished. computer began to act weird. closed everything and shut down. on restart, desktop was as if it just came from box. hd still had my icon and name and I existed as main and only user and my programs were still all installed in aplications, but no more public folder and no more files of mine. 30 gb of music and files vanished. norton unerase recovered about 20000 files, but about 60 or so were usable. the rest 0kb.

That's a Trojan horse. It was written a while back, but no one has heard about it in a long time.

Moral of the story: don't download pirated software from the Net.

[Chuckit]

Originally posted by Laurence:
This is not a virus, but in the future, I would recommend creating a non-admin user account on your computer and use it when you are downloading warez from an unknown source.

And also, realize that there is no way to compress Office down to 108 KB.

From what I've seen, about a third of what you find on P2P services is trojans. Paying a little attention would serve you well in the future.

[spork]

In my defense, I am not really a moron, just inexperienced and eager. Have of course definately learned my lesson.
Are there many more known trojans which affect OSX users and is there any kind of program to check dmg and sit files before or after opening to make sure they are clean.
thanks all,

[Spheric Harlot]

Originally posted by spork:
In my defense, I am not really a moron, just inexperienced and eager. Have of course definately learned my lesson.
Are there many more known trojans which affect OSX users and is there any kind of program to check dmg and sit files before or after opening to make sure they are clean.
thanks all,

No, and no.

However: If you're illegally downloading something called "Photoshop", and the thing is 40KB, chances are quite good that it's not going to be Photoshop.

Criminal activity can be SUCH a bitch.

*sigh*