As Aparajita astutely observed, the question seems to confuse [a] ease of writing malicious code and [b] ease of infecting a computer with malicious code. The two are very different concepts. The latter is a much more difficult barrier to cross.

A better question to ask is: “Assuming you are in possession of some malicious code, how easy it is to infect someone else's system running *nix vs Windows etc. with it?”

To understand the real issue, and many of the (often misguided), answers you're going to inevitably get to this question, you need to understand that as far as security is concerned, there are two worlds which are as far apart as one can imagine. People who come from these different worlds, are akin to the blind men describing the elephant by touching its different parts whenever they think about viruses, or computer security in general.

Once you realize this, and recognize the difference between these two worlds, you can quite easily tell which of the two worlds each of the answers on this page comes from.

Barry's answer partially covers this, but let me elaborate.

Unix/Linux/FreeBSD based systems were designed from the ground up with security in mind. Ken Thompson, who wrote the first version of Unix with Dennis Ritchie around 1969, gave an ACM Turing Award Lecture, "Reflections on trusting trust" (highly recommended reading) in 1984. Reading it today should provide some perspective of how much ahead of many of today's malicious hackers, Unix designers were, way back in the 70's and 80's. Unix had the concept of user/group, and separation of privileges from day one, well before computers became interconnected, and networking existed. This separation of privilege, extended later to separate ports , and separate processes running as separate headless users, for separate services running over TCP/IP. In contrast, fast forward to decades later, when Microsoft came up with a technology called Active-X, which allowed any malicious web site to run arbitrary code on a windows computer merely visiting the malicious web site. Active-X, arguably one of the worst ideas as far as computer security is concerned, was introduced decades after TCP/IP existed (mid 80's), and several years after the World-Wide-Web was invented (early 90's). Guess which "world" were the inventors of Active-X coming from? Was security anywhere on their minds at all?

In the Windows "world", the security model has, for years, been ignored or overlooked, to the point of becoming inverted. This is a world where:

• At least originally, a normal user and an administrator were one and the same
• A random click of a link or email-attachment might result in the installation of some software for which the user doesn't have source code, often coming from a random and untrusted source. Note that much of this behavior was dictated in the name of convenience and user friendliness, while rarely considering security as a worthy goal.
• High privileges, like those needed to read or write files, could travel through a single TCP port shared by many separate services (NETBIOS) all talking to a monolithic OS serving those files. In other words, crossing one barrier, provides the keys to the whole kingdom.

Now we are finally getting into viruses: users who live in the Windows world have been trained, for years, to treat security as an afterthought, or at best as some low priority goal. They are literally educated to always have an anti-virus installed, and religiously update their ever-growing black lists. Naturally, such users can't imagine life without the black-list approach to security. This is a completely "inverted" model turning security upside down: rather than preventing the infection in the 1st place, the security model of this world, accepts the file, and then compares it to a very long list of signatures to determine if there's a problem!

Contrast the above with the other world, represented notably by Linux these days, where what you allow, is white-list based, and everything else is forbidden, a world where:

• Software is available in source form to those interested in inspecting and auditing it
• Package repositories are administered by a single, trusted source
• Programs are only installed from cryptographically signed packages
• A new software package, rather than being executed directly, is first unpacked and installed using a dedicated and trusted package manager
• You can trivially inspect contents of packages before you install them
• Network services are strongly separated from each other by using different ports, different server programs, each running as an isolated process, with a separate user, and group than the main user of the system
• Different programs in general -- not just network services -- are isolated from others by various sand-boxing and application firewall techniques (see for example AppArmor which is standard on most Linux systems)
• Users can't accidentally install a package because installation requires special privileges, and having to enter an administrator password, to temporarily gain superuser status.

Ask a person coming from the inverted security model world a simple question: "How do you install new software on your computer?" Does the answer inlcude any of the following big-red-flag phrases?

• "Someone on a blog suggested" or
• "download from random web site X" or
• "Run the downloaded, install.exe to install", or
• "No worries, it is ok! I have anti-virus".

Now, ask them more fundamental questions:

• Do you know what your computer is running right now? (think stuff like svchost)
• Do you have an idea what is process X actually doing? Which files it has open? What other hosts it is connected to? Does it phone home periodically and sends your personal data to some mother-ship?

and watch-out for blank looks.

All the above questions are trivial to answer on Linux, by using standard tools like strace, lsof, or gdb, or in the rare cases where it is needed, by downloading the source code and inspecting it. How can your system be secure if you have no idea what you're running, all your software is an opaque black-box, and you have no way of auditing it?

The bottom line is that, in the *nix world, deep inspection and auditing of the system is trivial and accidental execution of software from unknown origins is extremely unlikely. An anti-virus software is unnecessary, and so no one who lives in this world, is feeling its absence, or being bothered by it.

And anyone who keeps repeating the accepted gospel fallacy "the reason that there are almost no documented viruses on *nix is because they are simply not enough of them to be worth attacking" is obviously coming from the inverted security paradigm world. First, today, there are way more *nix network connected devices (think smart-phones, both iPhones and Android, set-top boxes, cable-modems, routers, etc) than Windows ones. Also, most of today's most successful tech companies, like Google, Facebook, Netflix, and Amazon are running their services on Linux. Does anyone believe there's no value to attack there, or that the black hats aren't trying?

Edit: users who come from the inverted-security world, often introduce other Red-Herrings like "You don't need to be a superuser (‘administrator’ in Windows terms) to cause irreversible damage to your system". This is true, but totally beside the point. You cannot protect yourself against your own free will, so if you decide to delete your home directory with everything that's in it, no security can save you. The question, again, is: what's the attack vector? In the Windows world, many attack vectors exist because the so called surface of attack is very large by design (or lack thereof) and because it is a proprietary world where virtually all software comes as an opaque black-box. On *nix, these attack vectors are rare, and have been rare since the very start, because by fundamental design, the attack surface is much much smaller and easier to understand. Plus thanks to open source and full transparency of interfaces at all levels, anything you want to understand deeper, is right there for you, to inspect, audit, and study.

This is an old situation that has been true dot be explained away by simply saying that there are more Windows machines. The fact is that the numbers do not add up to that mistaken assumption.

In fact today there is only approximately 75% of actual Windows desktop users (not new sales, tat is where everyone get the story wrong) yet Windows suffers from more than 99% of viruses/malware. If it was a simple game of numbers then the two numbers should match exactly but they never have and still do not line up.

In fact no Mac has been infected for the past several years since Apple locked down the latest macOS security features so functionally Windows has 75% of the market with essentially 100% of malware.

When malware cheaters are arrested and sentenced to jail the are interviewed somewhere in that process and we occasionally have access to those statements. What the virus creators most say is that they hate Microsoft and attack Windows to punish Microsoft, for a wide variety of reasons. A smaller reason is that they are trying to steal from Microsoft customers and Windows is a much easier target because it is not a secure operate system.

Yes, it’s true.

Viruses evolved on the desktop, back when users shared files to floppy disks. Desktops were mostly CP/M, then DOS, then Windows. So there’s a huge amount of knowledge about how to create viruses for common desktop operating systems, which Linux is not. Why create a virus that targets 100,000 mostly computer-literate users with good security practices, when for the same effort you can target 100 million clueless people ?

When everyone got online and started sharing files that way, viruses followed. Generally, a user has to actually do something to get infected, such as executing a file. It didn’t help that Microsoft had this crazy idea back in Windows 95 to treat the web as an extension of the desktop (it was an option you could select, as I recall), so that the way to view a local movie (double-clicking) is the same way to execute an unknown file from some scuzzy website. In Linux, you’d have to change the file permissions to executable first, and either download it to your personal program folder (~/bin), or give an explicit path like “/home/dumbo/tmp/dodgy-file”. Much less chance of being tricked into doing that than following the wrong “Download” link on some website and getting virus.js instead of useful.msi

I can at least give two reasons for this, and both of it are nothing related to the inherent differences between Windows and MacOS.

1. Windows has more users than MacOS. It relates to how viral can malware be, and how easy can malware created for Windows (thanks to more software development particular for Windows).
2. Many commercial businesses rely themselves on Windows. While most top companies rely more on UNIXes known for their robust stability, middle and lower companies are inclined to Windows thanks to lower technological and maintenance barrier of knowledge needed.

These two reason essentially pushed malware creator to exist more on Windows’ platform and less on the others.

Immune to viruses?

There is a web page in Apple official website “why to buy mac? “. In that page they used to mention that Mac OS is immune to viruses. but apple itself admitted that mac OS is not immune to viruses anymore and they removed that line from that page. And that was in 2012.

Just FYI there is this trojan that effected over half a million Macs in 2012. So one thing is clear Mac OS is not immune to VIRUSES.

So now that we know.. Mac is not immune to viruses it's time to compare it with Windows..

Is mac more immune to viruses than Windows?

let me rephrase it.. does mac provide better protection against viruses when compared with Windows?

First of all, from past couple of years Windows user base and market share is huge compared to Mac OS. Since Windows is used by more people it's a much better target if u want to effect more systems.

So if u want to write a trojan or a virus which operating system do you choose to effect most computers?

the operating system that very less people use? or the one that most people use?

Now that mac OS market share is increasing as Apple is focusing on selling its products all around the world. it's not the case in Steve Jobs era.

so since Windows has a huge market share, its one of the top choice for hackers and virus coders. So from years there has been a lot of tools, scripts developed by several hackers for Windows and are available for next generation hackers.

And with the increase in market share and number of users, Mac OS has became a target for hackers. 2012’s Backdoor flashback trojan is the proof for that.

A point about Mac OS needs to be mentioned here. If I'm not wrong about the version number, the versions of Mac OS X and later were built around Unix kernel which is one among the oldest kernels and most secure kernel available as of today.

so simply one line answer, Mac OS is not immune to viruses. its just like Windows. but since the user base is less, it's not a target until the recent couple of years and now that it has a good market share. so it's a potential target for hacked and virus writers.

I hope my answer clears your doubt. Feel free to correct me if there's any mistake in my answer.

Have a great day. :)

Don’t lump Linux in with Windows when it comes to viruses. That is most misleading.

There are over a million Windows viruses “in the wild”. For Linux and Mac it’s a handful, mostly “proof of concept” viruses to show it can be done.

If you look into reality, you will realise that Macs are generally owned by people with more money than windows users, and are used by artists and musicians everywhere. Nice target, not remotely targeted.

The majority of the internet runs on Linux machines, as do local Governments, schools, universities, the international space station, news papers, banks, rendering farms, movie studios, plus an untold number of “smart devices”. And again, lots of lovely juicy targets, not being targeted.

Windows - no need to repeat the sorry saga of outages, crashes, updates that leave machines unbootable, viruses that bypass all known antivirus software, backdoors, etc.

Couple of things to note - antivirus software is reactive by nature. It awaits a known viral signature and acts on the files associated. Any virus that is new is unknown and so is harder to stop.

The broader point here is about engineering and design. MacOS is built on top of assorted bits of BSD (Unix). Linux is most similar to BSD, being “POSIX compliant” (a set of engineering/design standards). This is the main reason why there is such disparity between the numbers of viruses “available”. Linux enforces the standard that a user cannot run with administrator privileges. This means that any program run by the user cannot overwrite system files. This makes infecting the machine difficult. Macs offer this but don’t enforce it. Nevertheless there are protections running that look for unusual behaviour/attempts at writing to the system files area and password boxes appear.

The numbers are simply undeniable.

Of course, juicy targets are sought and multiple attempts made, they just used different methods to computer viruses.

Just to add to the opinions. I agree with the comment about backwards compatibility.

Windows was written before the internet was a major concern and Microsoft were in a hurry to write a user friendly interface for stand alone PC’s to compete with Apple’s first GUI (Graphical User Interface)

Apple’s current operating system is based on Unix - an operating system developed in universities crawling with teenage enthusiasts who just loved messing with other peoples data over the local system. No surprise that security was built in from the get go!

IMHO Apple’s real success was to manage to bolt a GUI onto a Unix kernel.

Considering the fact that Apple computers are in a minority - and that Apple are very defensive of their ‘Walled Garden’ approach to both software and hardware - it is not surprising that the majority of malware is directed elsewhere.

But malware and viruses do exist for the Apple OS and it would be stupid to think otherwise. What I find interesting is how often Apple puts out security updates!

The Mac OS is based off of BSD Unix. Unix is an open system and there are lots of independent people constantly poking and testing Unix/Linux operating systems looking for problems and issues. Bill Gates hired a guy from Apple when he was developing Windows and found out that lots of people at Apple and elsewhere know the ins and outs of Apple OS being based on BSD Unix. As a result, Bill didn’t want lots of programmers to know everything about Windows so Windows is kind of put together like a patch work quilt. Lots of programmers writing bits and pieces of code but only a few know how it is all put together. As a result, there are apparently lots of holes for hackers to tinker around with. These end up being exploits which hackers use to concoct viruses, worms, etc. Plus there are more Windows machines out there than Macs so the hackers make more money by the shear volume of Windows vs Mac. I believe there are about 125 Mac malware vs hundreds of thousands of Windows malware.

An Apple computer is a PC. PC stands for personal computer so Linux computers are also PCs too. If you mean Windows devices then it because of how it is written. Some people want to say it is because of market share but it isn't. Windows is a hot mess with code expanding for several decades and how its architecture is . Apple uses a form of Unix in OSX now MacOS. It was initially used by the NeXT computers developed by Steve Jobs in the mid 90s when he was booted from Apple and started another PC company ( as well as developing and working with Pixar). The way Unix works does not allow a programs to operate and used the system or its hardware. It is monitored and in its own sandbox. That is also the reason why Apple computers were not as good as Windows computers with gaming. In gaming the software is utilising the full resources of the graphics card and other hardware. In a Mac you couldn't and had to work within the system allowances. That is also why viruses are not prevalent on a Mac. There have only been three actual viruses on OSX (now MacOS) since 2001 and those exploits were covered and patched many years ago. There are ways to install code on a Mac but you have to have actual physical access to the device and allow the program to run and have permissions, not a true virus that is self replicating and activations. Malware is on Macs like Windows and Linux too and that is because they all three use the same protocols to access the internet. However malware is not a virus just like it is not a worm, Trojan, or other type and MacOS doesn't recognise .exe files anyway.

Linux has greater isolation between parts of the system whereas in Windows everything is in one big pool. That means it is harder to cross the boundaries in place in Linux whereas you have far less boundaries in Windows. Here is an example.

In Linux you a root account. This user account can make all kinds of changes to the system. If an attacker got access to the root account, they could wreck havoc on the entire system. Since you are not logged in as the root account, everything you do is kept separate from the root account except for when you need to temporarily borrow root access to make a quick change to the system. That is rare.

An attacker to gets hold of your standard user account has more difficulty accessing files owned by the root account or other users. Windows has a similar thing since Windows Vista called User Account Control, but it is much more limited than the isolation in Linux. The reason is the isolation levels in Linux is by design. It exists from the ground up whereas in Windows it is a patch.

Linux goes beyond the concept of user account control in a fundamental way. Individual file systems. When you log into a Linux machine, it looks like one system, but in reality is multiple separate system made to look like one. There is the root file system, the individual home directories, the boot file system is separate. Basically, a lot of separation in which the code in Linux works to weave together based on the security permissions of the person or program needing to access certain things.

Windows has good security, but Linux has a rougher edge that makes it less pleasant to try and breach. Add to that the fact that no two companies are going to run their Linux machines the same. Expert administrators are going to make fine tweaks that make Linux system at one company appear different than those elsewhere. Writing generic malware for that situation is possible but less profitable than targeting a Windows code and file systems that are perfectly consistent across most installations of the operating system.

Others who have responded are correct. You can infect and compromise Linux. It is more difficult, but user numbers do not account for the low interest in Linux exploits. Remember, Linux is the most installed operating system when you add up the millions of devices running Linux.

That includes the millions of Android devices, all the Chromebooks (which is Gentoo Linux remade), millions of the wired and wireless routers (home and corporate versions), most of the wearable gadgets, and well Linux is everywhere except laptops. And of course millions of servers between Facebook, Google, and Amazon combined. There is a lot of incentive there to breach Linux for fortune but as far as we know, most of those devices hold up pretty well given the design principles of Unix.

Why are Windows machines mostly attacked by malicious software than Unix and Linux machines?

Both Windows and Unix/Linux machines are attacked at about the same rate. (At work, it was about one attack every 15 to 20 minutes).

The attacks just don’t work very well against Unix and Linux (or BSD for that matter).

But Windows seems to have some inherent weaknesses that have never been fixed - like poor modularity (a patch for a bug tends to break other applications that depend on the bug for operation). Poor design that doesn’t isolate modules. And a rather weak security model that can’t seem to separate a user from the system reliably.

That is the usage share between Mac vs Windows.

Why would I write a virus that hardly affects less than 5% of people who use computers?

if you want to steal hell lot of money would you go to bank or just a street where some 10 people hanging around with frew $’s ?

I don’t think Windows is bad than Mac.

I think Mac is the worst, because Mac takes money for registering developer network even for customer buying computer. I disliked that, did bootcamp, and put Windows for Mac Book Air. Also, Mac is the worst for gaming. I don’t like their ports either. No freedom. (Don’t use USB. Use our thunderbolt!)

Windows

Pros

1. Very strong in gaming. DX11/12. Virtual Reality.
2. Strong in hardware engineering. CAD.
3. C# is not a bad programming language. I think better than Java.
4. Office is useful for works.
5. PowerShell is very useful.

Cons

1. Update program hell. Can’t work for half day because of update program.
2. Why, windows 8! Why did you adopt the Metro UI!!! This is hell unuseful for non-tablet PC users. I can’t understand why they copied smartphone UI from windows 8.
3. Hell security risks. Crackers make virus mostly specialized for Windows. Penetration testers find security hole mostly for windows. However, windows security is very weak. (Powershell weak security)
4. The nightmare of COM. COM was popular in XP age. Using COMs have very weak security. However, Windows programmer from XP age continue to use COM and don’t learn .NET. This is a nightmare.
5. CMD(DOS) sucks.

Mac

Pros

1. I like this clean UI!!!
2. BSD Unix based. You can use bash. There is package manager.
3. You can also use both unix commandline and designing in GUI.(Adobe CC, keynote) This is the hugest reason for creator/app developers using Mac.
4. UEFI terminal. You can setup dualboot with Linux using UEFI.

Cons

1. PC poor performance compared to price. They are not selling OS.
2. Developer Network takes high fee.
3. Thunderbolt and USB-C. Stop using this.
4. Horror of shortcut keys.

Linux

Pros

1. Free.
2. You can use the OS distribution you like. Ubuntu/debian/linux mint is the easiest. openSUSE supports opening Windows file. ArchLinux can work in PC which have low RAM. I can’t understand why people is using gentoo except for embedded system purpose.(Compile everything kills a lot of storage)
3. You can make your original GUI system. Go to debiantart. KDE, Xfce, and gnome are the major GUI system. Browse Xfce | Customization | DeviantArt
4. Soso good security. UFW, apparmor, and SELinux.
5. Open source. You can find kernel bugs easily in github or stackoverflow.
6. Very fast. Works fast in pentium PC. However, Windows OS in pentium PC is very slow.
7. Very useful for programmers.

Cons

1. Kernel panic is the horror for linux. Customizing too much make this happen.
2. Setting up GPU requires tough work.
3. Awful design software. Gimp is poorman’s photoshop. Inkscape. Moreover, LibreOffice is awful compared to keynote/powerpoint. However, I’m using it when presentation.
4. Weak language support except English.
5. You can’t live without CUI.

The number of viruses/malware for the Linux ecosystem is very low( they do exist, but are less in number). The fact is that Unix was built from the ground up to be a multi user operating system, unlike Windows. Also unlike an admin account on Windows; on Linux, you operate with limited privileges( you have to manually elevate yourself to " root"). Certain distros of Linux such as Ubuntu come with their own software center which increases the authenticity of the downloaded software.

Windows is hugely pirated, both the OS itself and the apps/ games written for it. The " cracks" for these stuff is a major source malware. On Linux, most stuff is free, so that possibility is not there.

" With enough eyes,all bugs are shallow". Since Linux is open source, anyone can take a look at the code and point out vulnerabilities. This is one of the main benefits of open source software.

Finally, there is the "security by obscurity" thing. Lesser the market share, lesser the attack vector.

Because you are mislead by someone?

Mac has viruses too, so does Linux, so does iOS. There is no major OS that doesn’t have viruses, bugs, exploits, issues.
It is only the people looking to mislead who say “Mac has no lags, stutters or hangs”, “Mac has no viruses”, “Mac makes a grain of salt perform better than an i9”

Mac definitely has lesser viruses because of one reason - Mac has less userbase. If I were making a virus, it would make less sense to make a Mac virus, knowing that about 10% of the Market is Mac, whereas >80% is Windows!
Also sadly, bigger fact is people who use Windows and Windows Laptops treat them like sh*t. If people respected Windows, obeyed the Warnings that Windows Defender and SmartScreen make, maintain Laptops like they do with Macs, Windows is just as secure if not more, will be just as long-lasting if not more!
And one last “problem” with Windows is the MUCH MUCH larger App Library from the Internet. Unlike Apple, Microsoft doesn’t have a leash on the developers and every app being made for Windows, so there are many Apps that are poorly coded or secretly malicious apps that users would install for the “Utilities” these apps advertise

Because of this (mostly): Desktop Operating System Market Share Worldwide | StatCounter Global Stats. With 75% of the global desktop market, windows is a very big target. You could try going after those other ‘small fry’ OSes, but you won’t see much of a return on the you invest in trying to infect those other OSes.

Windows is such a target rich environment, that even if your phishing email attack only succeeds 1% of the time, that can still be a few million computers infected. Same for malware, you might be trying to exploit a security flaw and even if, only, 1% of the computers are unpatched, you are going to infect a lot of machines.

It probably also doesn’t hurt that Windows is a pretty open OS. Anyone can write programs for it and make almost any type of hardware to plug into it. Microsoft can’t do anything about a security flaw in Open Office or Adobe Flash or Java, they can only close as many security holes in their own OS as they can find.

Most of the viruses that I see these days are social engineering attacks. You get an email from the ‘admin team’ declaring that your password has expired and that you MUST click this link or your account will be deactivated. You also get a lot of people that receive that delivery failure message from FedEx/UPS/Amazon with a convenient word document for you to open.

I also see people getting that ‘scary’ popup message that declares Microsoft has found a virus on their computer and that they must call this number or click this link so a technician can help (themselves to) hijack your computer. Alongside that popup vein, is the explosion of ‘download’ buttons that appear on a page. One takes you to the actual download and all the others take you to some scummy site trying to sell you something else or trying to install malware.

The other thing I have seen happen is people turning off the UAC (User account control), because it is such a major hassle to click a simple button every time they try to do something. That popup message from the UAC is a, step back from the computer and think about this for a second, pause to ensure that you really, really want to do this, because Microsoft cannot tell if you about to do something stupid or not.

Viruses are just computer programs, nothing more. They are written by programmers just like any other computer program and they are bound by the same restrictions.

Computer viruses tend to do a few things:

1. Replicate themselves so that they proliferate across multiple systems.
2. Hide from detection and prevent removal.
3. Ensure that they are run even if the owner of the computer doesn’t want them to.
4. Optionally: deliver some kind of payload, do damage, flash a message, anything really.

Points 1 and 4 are childishly simple. Anyone could write a computer program that makes a copy of itself, and “delivering a payload” is what every functional computer program does anyway by even functioning to begin with.

Points 2 and 3 are what makes viruses interesting. The authors need to be clever about writing their program so that it’s not easy to detect or remove. The virus programmer also needs to figure out a way to get their program to run, even if the computer’s owner doesn’t want it to.

These items usually mean the programmer needs to exploit some flaw or feature in the host operating system. In the very old days this would mean writing your virus code to the boot sector of a floppy disk, for instance, where it could get loaded before the operating system and piggy-back on top of that. Infection of executable files works in a similar way: you add your virus code somewhere in the existing program’s file, or tack it onto the end, and overwrite a tiny bit of the original program to jump to the virus code first and then back to where the original program was supposed to start from.

Hiding a virus is usually a matter of scrambling the code in some way so a signature isn’t easily determined and it becomes hard for antivirus products to detect. This evasion has become a true art form, but there’s nothing really special about it.

Now to get to your question: every virus needs to be tailor-made to the host operating environment or it won’t work. At the most basic level: executables compiled for Windows won’t even run on Linux or macOS without help. And even if they do, the environment looks completely different. Looking at a simple example: on an old MS-DOS PC you could assume that C:\COMMAND.COM would be present and would run at system startup. On a modern PC that file is gone, while on Macs and Linux it never even exited to begin with.. they don’t even have a concept of drive letters.

It’s these differences that make it difficult to keep all 4 balls in the air while also working across multiple platforms. As a virus author you’d have to keep track of so many contingencies it’d become impractical.

Interesting alternatives come in the form of script language malware. Scripts writting in languages like Python easily run on many platforms, and there’s nothing stopping you from writing a malicious script. The same goes for JavaScript and anything else that gets interpreted or JIT-compiled on the target platform.

Another interesting vector is emulation. Linux, for instance, has Wine which implements the Win32 API on Linux. This in turn would make it vulnerable to Win32 viruses because they suddenly do find a host environment that they can run on. Many of them would still fall flat because Wine is so much unlike Windows itself that viruses could get easily confused, but there’s a real vector there that Linux users often aren’t really prepared for.

Now do viruses actually attack Linux and Mac platforms? Yes, they do, but they are different viruses from the ones you see on Windows. They have to be tailor-made for the target platforms. Examples for Linux and Mac exist, but they aren’t very prolific “in the wild” so to speak. Linux and Mac are, however, in no way invulnerable to viruses or malware.

Hmm….I feel two major reasons “Why Windows OS are most prone to all types of malware and viruses?”

1. Popularity - Yes, Windows OS is the most widely used OS. Majority of people use it because of its simplicity, productivity softwares are on and written for Windows OS. So if some object is more famous then obviously more people are also interested in it to use, buy and see it. Same is with Windows OS, it is more popular than other OS, that means majority of persons is using it and that thing makes it more attractive for hackers to infect it.
2. Security - Windows is known for its less secure OS. I accept this fact that “UAC” feature makes their OS little more secure but It can’t change one big fact. I feel the most important step Microsoft should take to change its way of User Accounts. I mean in Linux OS when you’ll install any Linux OS on your system then by default you’ll be given a Standard account instead of Administrator account, but in Windows OS after installation you’ll be given an Administrator account.

Just wait here and think about it..

I hope this might help you :)

Feel free to ask!!

Thanks for asking!

I favour Linux, but a big factor in the lack of attacks has to do with population.

Lets say a virus is a lump of poop. Monkeys like to throw them at your house.

There are 850 to 900 monkeys throwing crap at windows houses, maybe 12-13 throwing it at OS X houses, and 2 or 3(at most) are throwing at Linux.

The OS X people are pretty good about paying someone else to keep the poop off their walls, and the linux people are very good at communicating when the monkeys appear. By the time the monkeys reach a linux yard, the gate is often locked and the siding is upgraded to teflon. So it doesn't take much work to keep the walls clean.

Anyway, that is the Linux scoop on monkey poop.

Just adding a few more information to what's already posted.

1. A computer virus is just a program that performs an operation without the consent of the user, usually malicious.
2. Linux like any OS is just another program which has design flaws and security shortcomings. That means that it's possible to develop malicious software on the Linux platform, as has happened in the past.

That said, Linux has 3 things going for it:

1. Faults get fixed quickly due to the large community and Linux's open source nature. Anyone with the time and knowledge can sit and fix an error.
   
2. It is not targeted by virus developers as much as other platforms
3. It has a more secure design than Windows, making the development and spread of viruses more difficult

Bottom line, Linux has had no major virus outbreak because no one made the effort yet, which is by no means a guarantee that it will stay that way forever.

It’s a combination of a few things:

1. In the interest of marketing and a superficial perception of “ease of use”, Microsoft has made a large number of bad engineering decision in the design of MS Windows what are not present in Linux. They regularly break the engineering credo: “make things only as simple as possible and no simpler”. This involves routine practices like undermining Window’s own security model by often having users run their accounts with administrative permissions. This allows those users to shoot themselves in the foot with total ease by doing stuff they don’t understand. Or be tricked into doing so.
   
   Microsoft’s IT culture model routinely confers power to users when those users don’t have sufficient understanding (i.e. a valid mental model) of their platform or the implications of their actions. This is fundamentally irresponsible on Microsoft’s part and creates the broken technology culture we see today. It’s a bit like giving a toddler a squeeze bottle of ketchup/tomato sauce. You can easily and very safely predict that someone’s going to make a horrible mess.
2. MS Windows users have a sense of learned helplessness about their platform - they’ve bought the marketing that “Microsoft will take care of them” even though that’s not the case. They don’t even try to learn how things work, because they’re consistently “protected” from knowledge and repercussions.
3. MS Windows is an effective monoculture which makes it fragile and very cost effective to exploit for malicious 3rd parties. Because of its proprietary, for-profit nature, it’s in MSFT’s interest to keep Windows installations a consistent as possible… but that also makes it completely predictable for any would-be crackers. Linux is far more diverse, with many different distributions who all do things somewhat differently, and any user has total autonomy and can do whatever they want. This makes Linux somewhat fragmented, but much much harder for malicious parties to exploit at scale.
4. Turns out that people who are locked in to a proprietary OS platform like Windows have almost no idea that anything else exists, much less an acceptance that it could both be better, or that they could move to such a better platform and leave the problems inherent in MSFT Windows behind.
   
   Ultimately, because of MSFT’s proprietary lock-in, normal market forces don’t work: users don’t properly punish MSFT for producing a poorly engineered product by ditching it and using something else. One thing’s for sure: being vulnerable (and creating a situation where nearly everyone runs “anti-virus” software - with a massive performance penalty for doing so - on their computers rather than just fixing the OS model) certainly hasn’t hurt MSFT’s bottom line. As a result, MSFT only offers lip-service to real security innovation.

The biggest reason Windows is afflicted by viruses is this: legions of woefully ignorant users + a platform that makes it easy for their ignorance to get them into deep trouble. In both cases, the blame for that falls on MSFT.

Note, others answering this question will argue that MSFT’s virus vulnerability is mostly due to the massive market share that MS Windows has, which attracts malevolent folks to exploit the platform… but that’s not really true if you think about it: Linux servers make up the vast bulk of Internet connected devices (i.e. 90+% of the “Cloud”, and most mobile devices, etc.) - a much larger market share overall than MS Windows has - and yet, there are no widely propagated viruses for Linux. The problem is specific to MS Windows, due to the points above.

There will obviously be people who answer this question with the standard trope that “very few people us Linux so it’s not a target”… this is absolutely bogus, because while not so many people use Linux on the desktop, it is used for a much larger number of servers than is Windows, and also just about every other device with a processor… whether Android, or TV’s or Fridges, or Space probes…

Linux is used in almost every banking / trading system and so security is taken very seriously….

You may see reports of bugs discovered, but if you patch on any reasonable schedule, then these are not an issue for you, as an independent audit discovered recently that security patches for Linux are generated faster than any other platform, with Microsoft second last.

All these things being the case makes a big difference, but as far as the desktop is concerned… actually the way the OS directs the user behaviour also has a large impact, I cannot tell you how many people I see logging in to Windows as “Administrator”, because “it’s just easier”… On Linux it’s actually not easier, and most distributions make it quite hard to do this,… Ubuntu for example would need manual alterations via the terminal to even make it possible to log in to a GUI session as the “root” user, and even then, some software even refuses to run as root.

So, the answer to your question IMO, is that it is a combination of the OS actually being more secure (which can be seen based on the types of security issues which present themselves in the CVE feed)… as well as more rapid patching, and user behaviour (some of which is guided by the distributions themselves)…

Types? Yes, they do much doing the same things, though in different ways.

Infection routes? The differences are in the details. Windows allows a much more open arrangement of permissions and securities ‘out of the box’ which lets viruses of various types easy means of infection. IF (notice I spelled that with a capital IF) a Windows user makes and takes the time and effort to learn how to adjust those permissions, then somehow figures out how to keep Windows from reverting those settings to default, which Windows has a serious penchant for doing during it’s updates and upgrades, then they can enjoy a Windows system that could be as secure as a Linux system. Windows, for some asinine reasons won’t allow those conditions to last so it’s absolutely necessary to go back through all the settings and reset them to proper values after every update. A Batch script file would help with this immensely. Ask Microsoft and the NSA why this is so … A careless or naive Linux user can allow viruses to enter and attack their systems through many of the same routes that viruses infect Windows, but they have to ALLOW it. Windows users most often don’t have to allow such to happen, Windows does, unless you prevent it as I mentioned above.

The same actual code? Not exactly. The file structure and permission differences between Windows and Linux requires different approaches.

No operation system will protect you from viruses.

There's no software that can stop all viruses.

Saying Mac’s or Linux have less susceptibility to viruses was marketing.

Computer viruses are not biological viruses. They aren't happy accidents of ionizing radiation striking strands of RNA. They are program made by people who want to do bad. And so, they obey the usual ways that humans behave when they want to do bad.

Means. Motive. And Opportunity.

Which operating system provides the fewest means? The ones with the fewest features. Which operating system is cutting back on features to attract users? None of them.

When you install programs and features you provide more opportunities for malicious people to attack. When you connect to the Internet you provide more opportunities to be attacked.

So what can you do?

Be diligent checking the source of software being installed. Delete apps you stopped using. Turn it off when you aren't using it. Turn it off and back on again to stop many things that maybe running in the background. Keep the software up to date. If something doesn't seem right and you think you may be hacked, turn it off.

Computers that are not on do not run viruses.

But generally, so long as people are motivated to do bad on a lot of devices while others are motivated to do new things on devices, viruses are coming.

Windows has a ridiculously outdated and inefficient core design. They have been slapping new themes and re-marketing this for decades. Usability and user experience has never been a windows priority.

To some life long windows users, the constant patching and updating have become a feature rather than a distraction. like the craving for a dirty cigarette. Most so call patches are fixes to issues that should not have existed before release or have been caused by previous patches. Updates are features that should have already existed or don’t really make a practical difference for retail consumers. Then there are driver updates and the lot.

Bean the popular PC OS at the time with the release of direct x, developers had more incentive to join the band wagon as graphic card designers started marketing hardware based on direct x support and boosting sales. Microsoft built a monopoly on windows 95 and direct x for pc gaming. If direct X was opensource Macs would have likely beaten Windows at gaming too. Said that, I love my Xbox.

Long story short - Windows should have been left for legacy like Internet Explorer. Sadly, Microsoft has more patching and upgrading instead.

For a long while a very significant difference is that OS X (as it was called) had full Unix style protection of the system, most of the OS was protected, and loaded applications could not gain access to the system files and settings.

Windows for the longest time allowed applications full access to the file system, which gave malware a bit of an easy target. With Vista onwards, Windows has improved its security model.

At the present time, both MacOS and Windows have a large set of security features which make it more difficult for malware to gain control of the system.

There are a bunch of technologies on both platforms which should make it impossible to gain control, but in reality occasionally expose vulnerabilities.

In terms of engineering, there isn’t a vast gulf between the two platforms. Security is like an arms race, it requires constant and repeated innovation to keep safe.

But the average Mac user is far less likely to encounter a problem because of other reasons.

• A lot of the Mac is actually open source software, while Windows is closed source. Security flaws in open software can be found and fixed by the global community.
• The Mac comes out of the box requiring all apps to be signed.
• The Mac comes out of the box without Flash or Java installed, these subsystems are major causes of malware issues.
• Many Mac users stick to the App store for their software, and apps delivered that way are sandboxed. So even if there is malware running, it can’t get at the file-system.
• The Mac user rarely has to do system maintenance, install third party drivers and so on. Because the average PC usually comes with a bunch of parts from multiple vendors, the user will end up installing drivers from all over the place.
• And the most important reason is that the global malware industry grew up on the PC. All their tools and all their methodologies are about Windows. So even if there is a glaring security hole on the Mac, it often goes unexploited because the community which exploits this stuff has 20 years of investment in the Windows platform.