http://www.geekzone.co.nz/foobar/6229The rumor of the bullet-proof Linux architecture
There is this rumor going around that Linux is virus free. It is said that the old-fashioned multi-user heritage of Linux (and other *nix OSs) prevents malware, since users are not normally running their programs in admin mode (as root user). We are reminded that execute bits are needed to run anything – contrary to Windows – and that execute bits aren't set on any attachments or files saved from emails or from a web-browser.
Therefore, we are told, the very architecture of Linux is so much more superior to Windows that it's just not possible to successfully spread malware. Of course – it is acknowledged – a low-level bug, a buffer overflow or other issue is exploitable. But nevertheless, users can't just catch a virus by email or downloading malware from the Internet, contrary to “those Windows users”. Linux will protect them from their own stupidity.
At least so the story goes. But sadly, that's not true. I will show how it is possible in a few easy steps to write a perfectly valid email borne virus for modern desktop Linux. I will do so not because I want to put down Linux. Quite the opposite: I like and support Linux, which is all I'm running at home and at work. I'm a big supporter of free and open software as readers of this blog will know. But if there are any security risks, even in my favorite OS or distribution then they will need to be discussed. Even more important: A false sense of security is worse than a lack of security. And unsubstantiated claims of superiority don't help in a reasonable discussion either.