Virus
From TheLinuxVault
There are very few viruses for Linux. There are no viruses that can attack a modern Linux installation because most of its components are open source. This means that the whole system is constantly updated by anybody who looks at the source code and finds a way to make it better. Most viruses for Linux came out after the security holes were already patched, and none were ever able to spread without deliberate installation, so they are only useful for research purposes. Linux systems have never had any risk of becoming infected by a virus, without intentionally installing one. [1] [2] [3] [4] [5]
On a Microsoft Windows system, vulnerabilities are found in the programming by malicious hackers constantly, even though they have no access to the source code. Microsoft requires every user of its product run a 3rd party anti-virus program on top of the Windows installation to be secure, which can use a lot of system resources. Even with an anti-virus program and a completely up-to-date system, Windows is still extremely vulnerable to viruses[6]. Linux does it differently; if a vulnerability is found, the vulnerable code that a virus would attack is removed or altered so that it is not vulnerable to viruses. This means that there are no viruses for Linux, and anti-virus software is completely useless on a Linux system, except to protect Windows machines.
