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Linux Viruses:

Even though in theory, Linux viruses exist, none is known to have caused any damage to a user, let alone propagate itself at the speed of light that is seen so often with viruses that affect Microsoft Operating system based computers.

A report by Dr. Nic Peeling and Dr Julian Satchell titled Analysis of the Impact of Open Source Software, "There are about 60,000 viruses known for Windows, 40 or so for the Macintosh, about 5 for commercial Unix versions, and perhaps 40 for Linux. Most of the Windows viruses are not important, but many hundreds have caused widespread damage. Two or three of the Macintosh viruses were widespread enough to be of importance. None of the Unix or Linux viruses became widespread - most were confined to the laboratory."

While neither Mac OS X nor linux can claim widespread reach and user base anywhere close to Windows, their growing popularity and acceptance does not mean that they will be more susceptible to viruses in the future. There are a number of factors that make linux a safer operating system. Not to say that it is 100% safe, as it would be a tall claim to make, but it is as safe as a desktop system can be.

Let us look at some reasons why linux is considered safer.

A) For a linux binary virus to be able to infect executables, the user activating the virus must have the permissions to write to the executables. Since in linux, the programs are in all probability owned by root and the user a non-privileged account holder, the chances of doing damage are insignificant.

B) Given the restrictions a non privileged user has confined to his/her own account, propagation of the virus is even more difficult.

C) Linux has many flavors and distributions built on a solid core derived from Unix. It also runs on many architectures and not just Intel based ones. Therefore a linux virus writer would have to understand the workings of each distribution and the various non standardized applications in order to make an impact. On the other hand, Windows has standardized applications such as Outlook Express and Outlook for Email, that not only allow for easy execution of viruses but have security flaws in them that is exploited by those who understand the way Windows based software are written.

Internet Explorer has been known to have bugs and security flaws making it's exploitation very easy. Moreover since the popular email clients from Microsoft such as Outlook and Outlook Express use the Internet Explorer to view html based emails, any flaws in Explorer affect the users of these mail clients from Microsoft. On the other hand, linux users are accustomed to the more popular Mozilla Mail, Kmail email clients that are not only more secure but also use the highly secure and proven Gecko Engine and the KHTML engine respectively.

E) The programming approach in Linux as well as the software developed for it is on the conservative side. By that it means that by default the permissions and options are severely restricted. For e.g. Attachments do not automatically run on linux systems. The user will have to go through a series of steps to make it run.

F) Even a non root user in Windows may be able to add DLL and other system files that can cause damage to the system.

G) Given that linux applications and system software are almost always open source, viruses may have a tough time to cloak itself in a open source piece of code.

While the linux kernel has excellent security at the lower level, the danger lies in application level programming. Therefore while currently Linux users can bask in the safety of their strong platforms, they will always need to be on their guard as virus writers try their best to win at least some battles if not the war.

Even though Linux users do not have to worry a lot about viruses that can affect the system itself, Linux can be a transit point for a number of viruses. Take for e.g. a mail server on the linux platform. Most viruses today are propagated by email using the security flaws inherent in Windows based applications. Since a majority of the email clients used are Windows based, those viruses can still propagate. Open source anti virus software such as clam v are robust applications that detect and prevent the propagation of these viruses. Thus even though viruses cannot do major damage to linux systems, appropriate precautions are always advised.

According to the Virus Library (http://www.viruslibrary.com/virusinfo/Linux.htm),some known Linux viruses are:

Worm.Linux.Slapper,Linux.OSF.8759, Linux.RST, Worm.Linux.Adm,

Worm.Linux.Cheese, Worm.Linux.Mighty, Worm.Linux.Ramen.

HYPERLINK "http://Worm.Linux.Ramen/"HYPERLINK "http://Worm.Linux.Ramen/"

HYPERLINK "http://Worm.Linux.Slapper/"HYPERLINK "http://Worm.Linux.Slapper/"

Linux Viruses:

Let us look at some reasons why linux is considered safer.

According to the Virus Library (http://www.viruslibrary.com/virusinfo/Linux.htm),some known Linux viruses are:

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