Search YouTube.
Or look on Secunia.com. There are hundreds of flaws on each Linux distro. The winner is Gentoo Linux with 3247 flaws. 24% of those flaws are highly critical.
Well I understand that every OS has it's own flaws but just how many of these exploits for Linux would lead to root access and the installation of malicious code to auto start?
I must admit it's something I haven't really looked into but I always felt Linux has the advantage of making malware harder to code being non standardised (different distros) whereas Windows is more common.