Free Linux Virus – Myth or Fact?

When we talk about Linux, Linux myth is completely virus free. But the fact is NO virus in Linux. Not much, but there is. Some IT experts believe that the more virus in Windows because the OS is more famous, and later when Linux is also being introduced there would be significant virus attacks as well. So if Linux would be similar to Windows in the future?

Linux is actually not the same as Windows, so they built on a different basis. Linux is even more similar to the Mac because both are built on UNIX systems.

But first we will discuss how a virus can infect Microsoft Windows. At least there are several ways, namely:

1. Access the program with indiscriminate, including downloadable application is infected (usually crack pirated)
2. The open space of the system. Usually go through the Internet or LAN. There used to be Windows virus called Nimda beagle and a well-known for its ability to spread in the network (this virus at the time revolutionary)
3. Careful not open the attachment file and link the website, including MS Office files that are infected.
4. Deceived by the appearance of the virus, such as a virus file disguised as a pornographic image file (generally done by the virus in Indonesia)
5. Infected through removeable media flash range.

The first one, there are fundamental differences between Windows and Linux, the file permissions problem. On Windows, especially home edition version (for versions bussines / corporate I have not tried, but there seems to be) unknown permissions of a file / folder. For example in Linux, if you possessed a file, that file will have three kinds of permissions, the user, group, and everybody. Each file permissions have three parameters are read (r), write (w), and executabled (x). so when we checked the file in Linux will get something like this:

-rwxr-xr-x 1 ferry disk 4401932 May 28 2011 unetbootin-linux-549

means to file the above: (read from the left by 3 digits)

1. user access rights with the rights owned ferry user read, write and executabled (rwx)
2. access rights are owned by group disk group with read permissions and executabled (rx)
3. everybody with access rights and executabled read permissions (rx)

Above files can only be read and executed by the disk group and everybody but can not be written by a user other than ferry.

Display permissions on Linux

This fundamental thing that makes Linux systems secure, in stark contrast to the first Windows.Awal Windows using FAT filesystem types that do not recognize the right of access. New in NTFS (from Windows NT, and then proceed to 2000, etc.), Windows introducing these permissions, but setting these permissions are not carried out directly. I am sure that many Windows users who do not know the permissions of a file. The new folder permissions will feel if your Windows computer has a username, usually between username Documents folder could not be opened.

Secondly, all executabled files (*. Exe – application) identified from the first few digits (header) of the file, usually the first 2 digits are the MZ. Unfortunately Windows reads a file instead of header files, but from the extension file, especially when displaying icon. So when there is a virus file in *. Vbs (VB Script), I was able to disguise this file in TXT, HTML and even JPG. Well this is done a few viruses that try to trick the user by posing as another file.

The third, when the Windows installation is complete, you will immediately be given a user with administrator rights. Indeed, in Windows 7 is no confirmation dialog asking user (emulate Linux / Mac?) When trying to write any suspicious file system. But how many users do not know the purpose of the dialogue than just click CONTINUE or CANCEL?

Confirmation dialog in Windows

I do not want to discuss whether Windows made with ugly or not, but three of the above that makes Windows extremely vulnerable to the virus.

And what about Linux? Wikipedia has recorded 29 virus, trojan 3, and the 12 worms that have been resolved. Virus-virus in Linux is mostly an application, so much is because an application has a gap. But that does not mean the virus-free Linux, Linux trend that is becoming increasingly easy to use can make the operating system is vulnerable to the virus. Users can not delete files on the system, but Linux now also has a large crack caused by an application that is currently widely used, ie sudo (switch user and do).

At the time of complete installation of Linux, usually it will ask password for user root (superuser). And the first user who installed the Ubuntu Linux administrators who will be able to mess up the system with additional sudo commands. Sudo command itself would make the user easily adjust the system, such as setting up a network, the installation of the application package, etc.. So when I would make a Linux virus, I will make sure that the virus I ask the user password with the command sudo, the new system as a whole is infected later. But the sudo command can also be restricted for each user, so in this case Linux already has a prevention.

Then how about a link or attachment that exploit gaps in the Internet browser or email client? In this case you can rest easy, because applications such as Internet browsers and email clients do not have write access to the file system. But plugins and add-on evil can ask for a password and create a startup file in a user’s home folder. For Ubuntu users with gnome, it will usually be placed in ~/.config/autostart (for the GNOME desktop) or~/.kde/Autostart (for KDE desktop). So Linux is not 100% free of virus. Linux itself has seen a gap in front of the eye.

Whether the virus in Linux can be transmitted through the flash? Answer is no. File permissions are not known to the FAT filesystem is usually dgunakan in flash. But in some versions of Ubuntu (as far as I 10:04), FAT filesystem mounted automatically with rwx permissions, start the Ubuntu version 10.10, the pattern is removed. Although a flash in Linux to run its autorun feature, but the execution of a script still requires user confirmation.

Fortunately, Linux itself is designed for multiuser. So if Linux is used in the office, it usually will have the username admin and regular users do not have the right to change the system, so there is no permission to use sudo on the list.

In conclusion, Linux is not 100% safe, there is a gap through the startup file, sudo, add-on, etc., the whole Linux and Mac is much more secure than Windows. So if you want a complete Operating System, and safely, use Linux.

I suggest the use of Linux for the office because it will be able to significantly reduce maintenance costs in terms of treatment against the virus. As an illustration, at the school where I teach, when we used Windows in years 2005-2006, the system re-installation is done every 6 months. But with Linux, I do not even need to reinstall for 1 more year, unless the update software like OpenOffice.

Let’s use the Linux and OpenSource, reduce piracy, hijacking is a sin, sinners place in hell.:)