Linux Security - How Can Your Linux Be Hacked Using Malware, Trojans, Worms, Web Scripts Etc.

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Is it possible that Linux can be infected with viruses? Probably, you heard of this in some debates. But here are some facts that you need to know to better understand how Linux is secured and what things can damage a Linux system. See how it is possible that Linux can be too infected and what are the percentages that you're currently with an infected Linux running on your computer.

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Introduction

First of all before I continue to speak anything about the topic, let me tell you that I've been using Linux for years now and never ever found any virus or virus-effect in any of my Linux systems.

There have been debates on the topic of whether Linux is virus-free or not. I have been in Linux environment for years and heard infinite numbers of Windows users accepting "Linux Is Virus Free". Many of such Windows users turned to Linux, actually I'm one of them. Although, I do use Windows for tutorial purposes several times in a month, but for regular, I'm a Linux user. 

Is "Linux Virus-Free" A Myth ?

It won't be correct to answer it in Yes or No. The question raises big debates that I don't want to create here. But I will answer it saying that Linux is one of the most secure operating systems available when we only talk about the "system only" and leave everything else that happen inside that system. For example, running vulnerable third-party applications on Linux, users errors etc. It happens many times that the user is running an outdated application. Running outdated application can cause users be tricked by any attacker. When the newer version of any application is released, the developers or company informs all the new stuff that newer version has, including bug fixes and fixed security holes. Attackers take benefit of this information and find people who are still using an outdated and vulnerable application. Attackers/Hackers know exactly what vulnerabilities they need to target and how.

Although Linux system is very powerful and Linux developers provide updates frequently to secure users but those third-party applications may not be as good at security as Linux developers are. So the answer is very clear of how Linux is Virus-Free and how not.

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Do We Also Have Viruses For Linux ?

Everyone who runs Windows or even one who does not, knows very well that there are viruses for Windows. Actually many viruses for Windows. But what about Linux? Are there viruses for Linux? The clear answer is YES. There are viruses, trojans, worms and other types of malware that affect the Linux operating system but not many. Very few viruses are for Linux and most are not of that high quality, Windows-like viruses that can cause doom for you. Although Linux kernel is memory resident and read-only, so infection seriousness depends on with what permissions that malware was run. If the malware or trojan was run without root permission then it can cause temporary infection but if malware or trojan was run with the root access then it can infect the entire system.

Getting Infected By A Windows Machine

Having not many viruses for Linux does make Linux users secure but not careless. There are many other ways that Linux can be too infected and one of the major reasons is Windows. Most users whether using Linux server or desktop, they are connected to a Windows computer on a local network to share documents, files and other stuff. It is very much possible that Linux user accepts a file which is a virus and capable of executing on Linux too.

There are viruses that can execute under Windows and Linux both. So users need to be extra careful when receiving files from a Windows machine. 

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Downloading Applications From Unauthenticated Sources

Another and very powerful way of attackers to infect your Linux is by providing you an app with some interesting functionalities. You download it and keep on using it without knowing that the application is sending your information out to the attacker who coded this application. That's why it is always suggested to download/install applications from the authenticated places on the web. I've talked to some Ubuntu developers and they always suggested to use software center as much as possible. Although I have used other resources but all of them were secure and trustable. If you want any application that you don't find in software center, you can leave an entry on our contact form and we'll provide you application with all the information about it.

User Errors

User errors can be the most harmful for a Linux system because in this user himself provides root access to a malware. This happens when an unauthenticated application is installed on the system and application has some basic features that user likes. While the user was installing this malicious application he was asked to provide root access, and the user did. Now the application goes up to its most dangerous face and infects the entire Linux system. Running a malicious program without root access can be dangerous but it won't be permanent. After the restart, the system can recover from the effects that were caused by the virus.

Linux Viruses - Precautions To Adopt To Secure Linux System

So all the above-mentioned security risks are possible. So why not take precautions. Here are some precautions adopting them will provide you the extra security and your most powerful Linux system won't be infected.

1. Be Careful

All of the above-mentioned security risks are rare and only occurs when the user is careless. So whether the Linux user is new or advance, the first precaution is "Don't Be Careless". Being careless can cause the system severe damage. Double check before you receive any file from the Windows system, don't install software from malicious website that promise to crack the password or any such illegal promises. Install software from the system provided software center and repositories. If you need any application that is not available in the default system repositories then there are many trustable resources that you can download the applications from. 

2. Anti-virus Scanners

One of the most debated topics is whether Linux needs an antivirus or not. I will mention some of the facts and based on those facts you can decide to install or not install an antivirus in your Linux system. Let's go ahead and see some fundamentals of antivirus.

In simple terms, an antivirus is a set of tools that scans the device to find malicious programs, viruses, trojans and hundreds of other types of threats that can damage one's system and then trash all the threats out of the system.

Antiviruses companies are working very hard to code definitions of the latest viruses. All these new definitions can recognise latest and more advanced viruses and delete them as quickly as possible. Now one thing to be noticed here why a Linux system might require an antivirus.

Why Linux Require An Antivirus ?

A user needs to decide himself whether he needs any antivirus or not without going into the debates. First of all there are not many viruses for the Linux OS so it's very rare that user system is infected with a "Linux type" virus. And secondly, there are hundreds and thousands of viruses for Windows. For a Linux system alone you might not require any antivirus but if you have Windows files in your Linux so there are higher chances of getting infected with those viruses, if they are able to execute on Linux too. Even if those viruses are not executable in Linux then they'll wait for a Windows system to execute their malicious programs.

The latest study of Kaspersky for the first quarter of 2015 shows how Linux system have been used to DDoS. You can read the full report here.

You can decide to use an antivirus scanner (not the full suit) to scan the viruses contained with Windows files. The antivirus scanner will scan all the files and find out the viruses or threats that you can remove manually via terminal. But you're all free to install a complete suit to protect from Windows viruses. Below are two of the popular antivirus scanners that you can use for free. Other popular antivirus also provide free scanners for Linux. Google for any other antivirus if you want.

Clam AV

Comodo Antivirus For Linux

Download

Download

Conclusion

Now so many people will take it wrong way to install any antivirus for Linux but here is an important thing to be understood. There are for sure few viruses for Linux and most of them are not of high quality and destructive. But there are still Windows viruses that can spread across the system if executable on Linux. Even if viruses can not execute in Linux they will still spread when the Linux user transfers data to a Windows system. So to find the threats and delete them, we Linux users can install antivirus scanner. Those who don't store Windows files or do not connect with Windows machines they might skip installing antivirus scanner but still they need to be careful.

Finally tell us your point of view or Linux experience with us and share with us any story where any user had virus effects in Linux.