Quote Originally Posted by andrewdodd13
Don't be complacent, linux is still susceptible to virii, its just not as common because the general idea is that the gullible users use windows, so most virii creators target that.
Here is a good explanation as to why linux is not susceptible to viruses.
I have heard that LINUX does not suffer from virus attacks. Is it true that there is no threat of viruses with UNIX systems?

A virus is a program that replicates itself by modifying the system on which it runs. It may do other damage. Viruses are small programs that exploit social engineering, logistics, and the inherent flexibility of a computer system to do undesirable things.

Because a UNIX system does not allow this kind of flexibility in the first place, there is categorically no such thing as a virus for it. For example, UNIX inherently restricts access to files outside the user's privilege space, so a virus would have nothing to infect.

However, although LINUX cannot itself execute a virus, it may be able to pass on a virus meant for a Windows machine should a LINUX machine act as a mail or file server. To avoid this problem, numerous virus detection programs for LINUX are now becoming available. It's what is meant by virus-software-for-LINUX.

On the other hand, conditions sometimes allow an intelligent hacker to target a machine and eventually gain access. The hacker may also mechanically try to attack a large number of machines by using custom programs. The hacker may go one step further to cause those machines that are compromised to begin executing those same programs. At some point, this crosses the definition of what is called a "worm." A worm is a thwarting of security that exploits the same security hole recursively through a network. See the question on security below.

At some point in the future, a large number of users may be using the same proprietary desktop application that has some security vulnerability in it. If this were to support a virus, it would only be able to damage the user's restricted space, but then it would be the application that is insecure, not LINUX per se.

Remember also that with LINUX, a sufficient understanding of the system makes it possible to easily detect and repair the corruption, without have to do anything drastic, like reinstalling or buying expensive virus detection software.