The core reason you don’t need an antivirus on Linux is that very little Linux malware exists in the wild. Malware for Windows is extremely common. Shady advertisements push nasty software that is practically malware, file-sharing sites are full of infected programs, and malicious individuals target security vulnerabilities to install Windows malware without your permission. With this in mind, using an antivirus program on Windows is an important layer of protection.
However, you are very unlikely to stumble on – and be infected by – a Linux virus in the same way you would be infected by a piece of malware on Windows.
Whatever the reason, Linux malware isn’t all over the Internet like Windows malware is. Using an antivirus is completely unnecessary for desktop Linux users.
Package Managers and Software Repositories: When you want to install a new program on your Windows desktop, you head to Google and search for the program. When you want to install most programs on Linux, you open your package manager and download it from your Linux distribution’s software repositories. These repositories contain trusted software that has been vetted by your Linux distribution – users aren’t in the habit of downloading and running arbitrary software.
Other Security Features: Microsoft has been doing a lot of work to fix serious security problems with Windows. Until UAC was introduced with Windows Vista, Windows users almost always used the Administrator account all the time. Linux users normally used limited user accounts and became the root user only when necessary. Linux also has other security features, like AppArmor and SELinux.
Market Share and Demographics: Linux has historically had low market share. It has also been the domain of geeks that tend to be more computer-literate. Compared to Windows, it’s not nearly as big or easy a target.
Keep Your Software Updated: In an age when browsers and their plug-ins – particularly Java and Flash – are the top targets, staying up-to-date with the latest security patches is important. The biggest malware problem on Mac OS X was caused by the Java plug-in. With a cross-platform piece of software like Java, the same vulnerability can work on Windows, Mac, and Linux. On Linux, you can update all your software with a single, integrated updater.
Don’t Run Commands You Don’t Trust: The Linux command prompt is powerful. Before you copy-paste a command you read somewhere into the terminal, ask yourself whether you trust the source. It could be one of the 8 Deadly Commands You Should Never Run on Linux.
Antivirus software isn’t entirely useless on Linux. If you are running a Linux-based file server or mail server, you will probably want to use antivirus software. If you don’t, infected Windows computers may upload infected files to your Linux machine, allowing it to infect other Windows systems.
The antivirus software will scan for Windows malware and delete it. It isn’t protecting your Linux system – it’s protecting the Windows computers from themselves.
You can also use a Linux live CD to scan a Windows system for malware.