Why most of the viruses are being written for windows? what does linux have to prevents virus writter to write viruses for Linux.

it has a stronger user rights model and better fundamental resource handling, but to be honest it's the number of users. why write a virus for less than what... 5% of computers when you could write one that affects over 80%?

And even within these 5%, the systems vary so much, that a virus couldn't easily affect another machine: one system might be vulnerable to the virus, but the next system might have a former or a later version of the program/kernel (which might not be vulnerable to this specific attack) - in contrast to Windows where most people have Windows XP with SP 1/2 and IE 6.

Use the search function on this site to check out similar threads. This question seems to be asked several times every week.

It's also because virii rely as much on social engineering as destructive instructions to the system.

Most Linux users have learned to execute only code that everyone else has vouched for, case in point repositories. Users of other systems, once they see an attachment from someone they trust, don't hesitate to click on it, unleashing the virus and quite likely wiping out their system.

One of the most powerful weapons of penetration is deception. That applies in war as well as viruses.

It has nothing to do with the number of users... many of the server systems running the internet are Linux systems... It's because Linux security models are different, and virus propogation from it is not very efficient.

The number of users thing is M$ FUD...

no it's not, how many firefox flaws were found when no bugger used it? how many are found since 1.0? I know in theory being in beta or rc implies it's allowed to have them but with FF on the up and up in windows as well as Linux, a lot more flaws and exploits have been found in it.

The security model in linux is a lot better and viruses are less likely to do damage etc.. but those holes do still exist and can be exploited.

It's not entirely FUD - part of it IS the fact that Windows is the largest share of the market.

Think of it this way: many of the viruses that users get on their system are in email attachments. It could be a message saying "reallycutepictureofmykidathisbirthdayparty.bat click it now to check it out" or "gorgeous hot babe with blahblahblahblahblah.vbs" and while it's not a pure virus, but a trojan horse, it has a viral effect because the idiots who are the type to open every single attachment are the type who forward it on to others first THEN open it. It is well worth noting though, that in most cases on *nix (where the user is NOT root and not a member of the root group) even an rm -rf / won't damage the system itself - it'll just wipe out the user's own home directory and environment, which while not being a great thing, is a good lesson in not being an idiot.

If Linux were more widespread, you can be sure that at least trojan horses would be a bigger problem in the *nix-using community - but right now even if there were a strong effort to infect *nix that way, probably better than 99% of Linux users would be clueful enough not to run shell scripts without knowing exactly what they do. Would you run an .sh attachment from an untrusted source? I sure wouldn't - at least not without reading it line for line first - and for me to run it, not only would it have to come from a trusted source, it'd have to be in a .tar/.dar file before I'd even check it out - I'd delete it without checking it otherwise.

Most wndows users are clueless. "Oh look it says click here, ok."

The plural of virus is viruses, not virii. Read the security references and do a search of the forum/Google, this question and which distro should I use? are asked every few days.

The simple fact that most Linux users run as "user" and not as root keeps thing like viruses , spyware from being a problem.Since most softare require root access to install.

*nix systems are bad breeding grounds for virii

the reasons for this first off, is unix operates on a file structure that is a lot idfferent that windows,

windows is also easy to infect because the registry is very vunerable \\

windows also doesnt recover very well because it depends too much on the registry being perfect

linux and unix have compartments and if one is infected, then a section of your system will not function
sometimes its a lot more verbose about whats going on

unix is simply a system that is more likely to run the infected code, yet not be affected by it

windows is also automated to a great degree,

and yes i do agree, email attachments, very stupid

i agree with those who have said,

unix viruses are not likely to be executed because the usually come in the form of scripts run by a shell

you can easily open the file and see what the script will do

in windows, its a compiled binary (.exe) or other, you would have to reverse engineer it to see it
most windows users would even bother to look at the souce HTML of the web page they view

most user just dont think that way

most linux users are big computer geeks, this is somthing that sparks curiosity.
they are always looking at source code anyway

Are you sure about that? I mean, if I were to create a virus for Unix, I wouldn't implement it as a shell script, but rather as binary.

if you created a binary virus, i wouldn't install it

any sensible linux user would download binaries from moderated sites that are trusted

so yes im shure, i would install any old binary

utility scripts however are more of a risk because you copy the source and run it

or you could write one yourself and create problems if its buggy, especialy if it runs as root

sorry wouldnt install any old binary

That's right, but suppose you could break into a trusted site, say, a Debian mirror, and alter the files? Then it wouldn't matter whether a script or a binary contains the virus, and I guess that it's often easier to implement a virus in C than in Bash (especially when exploiting buffer overruns).