"According to new research published by Evans Data this week, a
significant majority of Linux servers have never been infected with
a virus and have never been compromised by a malicious attack.
"A word of caution though: The results come from a July survey
of only 500 Linux developers. In that survey, 78 percent of
respondents reported that they have never had a Linux server
compromised by a malicious hacking activity, while 92 percent
claimed that they have never had a Linux machine infected with a
virus. The survey results stand in stark contrast with Evans Data's
own spring survey of non-Linux developers, in which 60 percent
admitted that they had a security breach, and a full 32 percent
actually had three or more breaches. Only 7 percent of Linux users
reported having three or more breaches..."