There seems to be a false sense of security among some Linux users. The number of malicious programs specifically written for GNU/Linux has been on the increase in recent years and in the year of 2005 alone has more than doubled: from 422 to 863. Some security consultants will argue that Linux has fewer viruses/malwares because it is less attractive as a target for having a smaller user base (compare ~90.66% Windows vs ~0.93% Linux). You may call me a traitor but I agree with that assessment. There is no reason why we will not see a rise of malware designed for Linux as it becomes more mainstream among ordinary users.
I’ve heard so many times from beginners “do I need an anti-virus?”, “Linux has no viruses”, “There’s no way a virus could infect a Linux box”. This is the false sense of security that many new Linux users are dealing with today. Most are just starting out as Linux users and have no idea about the risks and safe actions to take. Newbie Linux users tends to feel safe with statements they read about how the Linux OS could never be infected and if so could never be executed because of the way files works under Linux.
Linux does have its share of viruses, trojans and worms but would the Linux infected binaries really need to be exclusively executed by root for a major system apocalypse? Although in most cases the system programs are owned by root and the user is just running the program from a non-privileged account. Some people will argue that for a system wide infection, the infected binary would have to be derived exclusively from root and as a non-privileged user, by running an infected program would only effect the users /home directory and not a system wide infection.
There is a method to infect a system wide Linux OS without the need to become root, this procedure is a commonly known as “Privilege escalation” –
“Privilege escalation is the act of exploiting a bug or design fault in a software application to gain access to resources which normally would have been protected from an application or user. The result is that the application performs actions with more privileges than intended by the application developer or system administrator” (Privilege escalation).
Its not very likely that Linux malwares will ever compare to that of the Windows viruses and even more unlikely that Linux will ever see its share of the same issues with malware as the Windows operating system. If you take into consideration the email-borne viruses that Microsoft has, they are all executable and are in most cases executed by the user, whereas with Linux you would have to save the file make the file executable and manually run the file. Windows XP automatically makes the first named user an administrator, with the power to do anything to the system. Linux on the other hand uses the first named user as the root administrator but does not allow root login on boot-up.
As a Linux user, using the repositories, md5 checksums and using root privileges only when necessary are just a few ways to to guard against an intrusion. SSH is often the first point of entry to a Linux system but it’s not the last line of defense. Using a strong password and anti-virus software should always be common practice for any OS and could potentially limit the risk of a system catastrophe.