There has been a lot of debate recently over whether or not it’s a good idea to run an anti-virus program if you’re using Linux. Reading the forums, I see a lot of misunderstandings, particularly around what exactly it is that these anti-virus programs do and whether or not they’re necessary. I hope to clear up some of the confusion regarding the anti-virus situation on Linux.
What a Linux anti-virus is!
When you think of an anti-virus program, especially if you’re coming from a Windows world or using the best spyware remover, you think of a program that runs in the background and scans files as they are accessed (or, perhaps you have your entire system scanned on a regular basis) to see if anything is infected with a virus. This is an effective way of detecting and removing viruses on a desktop computer; and for a Windows machine, it’s all but a necessity given the vast amount of threats circulating on the Internet.
Linux anti-virus programs don’t work this way, because Linux anti-virus programs aren’t meant to protect the desktop machine from Linux viruses. An anti-virus program running on Linux is designed to detect Windows viruses, so that they aren’t spread, unknowingly, by the Linux user.
So why care about Windows viruses on Linux?
If you’re running Linux, you are, in a practicality, immune from a Windows virus. So why would you want to bother scanning your files – files that won’t work on your computer, anyway (except, for example, through Wine) – for viruses that have no effect on you? Well, the simple answer is, you wouldn’t. But it is more complex than that. I’ll explain.
The vast majority of Linux anti-virus programs run on mail servers. These are the computers that your mail client connects to when you want to send or receive an email. Since email is one of the main way viruses and trojan horses spread, these servers are the “front-line” in the battle to stop computer viruses. And, since so many of these servers run Linux, it’s clear to see the need for a Linux program to detect Windows viruses. If you’re running a mail server, whether it be for your home or office, you should definitely be using an anti-virus program to intercept any naughty files that might be trying to move in or out of your network via email.
Another place where you’d want to run an anti-virus program is on a file server shared my multiple users, even if you trust all of these users. File servers are basically repositories for data; some of that data might come to exist on your server through legitimate sources, but there’s no way for you to know where each and every file originated. Running an anti-virus ensures that if someone uploads an infected file, say, downloaded from a Peer-to-Peer network, your file server will detect the threat and stop any other users from becoming infected.
So what about Linux on the desktop?
Now that you understand what exactly these anti-virus programs for Linux do, it’s up to you to decide whether or not you want to implement them if you’re just running a standard Linux desktop machine. If you have Windows computers on your network, and you’re sharing files, it’s probably a good idea to run something like ClamAV, to keep those other machines safe.
Let me explain how I use my Linux Anti-Virus program on my desktop. I use ClamAV, but I don’t keep it running in the background (this uses up resources, and since I’m not running a mail server or transferring lots of files, it really isn’t necessary). I only use it from the command line when there is a specific file of questionable legitimacy I want to test; this is a great service I can provide to Windows-using friends. Since I’m immune to these viruses, I can check out files before they download them.
I hope I’ve cleared up some of the confusing around Linux anti-virus programs, and that I’ve answered the oft-repeated question, “Do I need to run an Anti-Virus on Linux?” In reality, the type of setup you have, and the quantity of your paranoia dictate the answer to this question; but for most people, it simply isn’t necessary to run an anti-virus in Linux.