I was at DefCon this weekend and there were actually several talks about OS X vulnerabilities. And yes, they are real threats, but media tends to exaggerate them because:
1) Reporters are not engineers and thus, do not fully understand the problem.
2) Their articles get more circulation if they over-hype the problem.
Nobody is saying that OS X is malware-proof. But OSX, BSD, Linux and Unix all have inherent design features which make them more secure than Windows. The biggest and most important is a concept called Discretionary Access Control. Allow me to explain...
Alll *nix-based systems have a user called "root". This is a super user that can control the entire computer. In order to install software, you must first become root. In order to read or change configuration files, you must become root. If you want to modify an executable, add a shared library, modify a device driver, or change anything meaningful, you must first become root. This makes it next to impossible for a regular user to unwittingly install a virus or any piece of malware on his computer because, in order to do so, he would need root permission. This is called "Discretionary Access Control", or DAC for short.
Most Windows users will tell you that this is akin to the "Administrator" account on your PC, but that is not exactly the case. Microsoft has attempted to emulate this technique many times, but always fails miserably in its implementation. On a typical Windows PC, THE DEFAULT USER ACCOUNT has Administrator access! This makes it very easy for users to unwittingly install all kinds of malware on their computer without realizing it. Think about that for a second... why would you ever need to run a word processor or a web browser as a super user? That would mean that Internet Explorer, for example, would have permission to write to your system32 directory! Why would IE ever need to do that? And what person in their right mind would ever allow it to? It's a virus writer's dream come true.
Now let's talk about software vulnerabilities. Try to stay with me here, because this gets complicated. The vast majority of software vulnerabilities (greater than 90%) involve buffer overflow attacks. This is an attack, where by a malicious user takes control of a running program and shoe-horns its own malicious code onto the instruction stack. When this happens, the malicious instructions have the same permissions as the program it just took over. And what permissions would those be?... it depends on which user is executing the program. When you run everything as Administrator, as is the default behavior in Windows, EVERY vulnerability becomes a critical vulnerability and EVERY piece of malware can run as a super user.
Let's back up... I'm sure that by now, the Microsoft crowd is saying "Wait a second! You don't have to run everything as Administrator! You can create regular user accounts and restrict their permissions too." And they would be correct. I have never met anyone who does this on their home PC, but the option is certainly there. But even if you do that, you're still screwed because EVERY SINGLE BACKGROUND SERVICE runs as Administrator. Oh, you forgot about the background services, didn't you? Don't feel bad... Microsoft forgot about them too. Right click on "My Computer", select "Manage", and click "Services" if you want to see I'm talking about. There you can see nearly a hundred services, all running as Administrator! Break any one of them and you have Administrator access to the entire computer. Nice, huh?
But wait, you say, doesn't Mac OS have that same problem? Of course not. Only an idiot would run everything as super user. Mac OS comes from the factory with FORTY different user accounts, one for every background service that it runs. (Most flavors of Linux do this as well.) So if you happen to exploit one of them, you can only do what that small, very restricted user account can do... and it isn't much. In fact, when you buy a computer from Apple, they don't even give you the root password! You only have access to your user account... your own little world. And if you mess it up, you're not going to take down the entire computer. You'll only screw up your own account because you don't have the required permissions to screw up the rest of the OS. So the underlying architecture of Mac OS is inherently more secure.
Keep in mind that this *DARN*-poor excuse for a DAC is one of a thousand flaws with Windows. I could go on for days about the absolutely retarded design decisions made by Microsoft. Remember the outbreak of email viruses about 5 years ago? Know why those were such a big problem? Because some genius at Microsoft said, "Hey! Let's invent a scripting language that allows user to embed executable code into email messages and then execute that code automatically when you open the message!" Brilliant, huh? It's like they put that hole there on purpose so that every script kiddie with a copy of Microsoft Word could write CRIPPLING email viruses that took down servers and cost billions of dollars to fix.
The issue is much more fundamental than people think. People who use the "security through obscurity" line clearly do not comprehend the issue.
