It is common to hear statements like "I can't possibly have a virus, because I use Linux" or "There aren't any viruses on Macs". It is very well known that these ideas are completely false. Here is a good place to look at why.
In a previous article about basic access control mechanisms in systems security we introduced Mandatory Access Control (MAC) as a more accurate mechamism than basic access control. Now we are talking about of SELinux as an example of Mandatory Access Control.