That's kind of a scary place to put yourself in. I see this a lot with the Apple folks too. Honestly, how to do know you have no viruses, malware, sniffers, etc if you have nothing watching for it? It's like taking all locks, alarms, and cameras off your home and then proudly stating that you know it has never been broken into. How do you know that no one has walked into your home, made some toast, cleaned up after themselves and left?
I watch Apple users take this same approach, get a malicious add-in on their browser, and then wonder why their system runs slow. Granted, the majority of the bad stuff is focused towards Microsoft, but that doesn't mean it can't happen on other systems. At all the hacker conventions, EVERY OS gets hacked. On Linux, you are safer than being on Windows, but you are kidding yourself by doing nothing.
Browser get hacked but the Unix OS’s don’t get hacked unless you have a really easy root passwd.
“Honestly, how to do know you have no viruses, malware, sniffers, etc if you have nothing watching for it?”
Because the fundamental design of the OS precludes such things from happening.
To use your home security example:
Windows was like a home with absolutely no locks, alarms, etc. which had them retrofitted later as burglars did their thing, requiring a profusion of keys and monthly live monitoring service costs. New security must be installed by the user whenever someone finds another way in, such as cutting holes in the walls or crawling thru ducts. Word is Windows 10 will offer any passer-by the house key along with suggestion they come in and make toast.
UNIX (which OS X is a robust implementation of) is like a house built with strong security implemented everywhere from the beginning, from biometric locks on every door to bulletproof windows and stone walls. Viable attacks are rare and pervasively addressed by the builder; most attacks are either academic (requiring very specific conditions & tools) or require gratuitous stupidity on the user’s part (like opening every door at the explicit request of shady-looking strangers). Viruses aren’t a problem because every surface is treated with Micro-Ban (kills microbes on contact). Malware isn’t a problem unless the user explicitly provides the root password to suspicious software which has no reason to request such access. Sniffers aren’t a problem because sensitive information is encrypted. I know that nobody has walked into my home, made toast, cleaned up and left because the front door is ALWAYS locked, the windows & walls are unbreakable (short of serious power tools leaving a proliferation of evidence), the pantry won’t open without biometric clearance (I never think of it because it recognizes my fingerprints on contact), and security logs record every room entered & exited and every door opening; insofar as any of those security features CAN be broken/beaten, doing so (without observable consequence!) would require effort far beyond the payoff of making toast.
# time chkrootkit
ROOTDIR is `/'
Checking `amd'... not found
Checking `basename'... not infected
Checking `biff'... not found
Checking `chfn'... not infected
===big chunk of stuff snipped===
chkutmp: nothing deleted
Checking `OSX_RSPLUG'... not infected
real 0m2.942s
user 0m1.373s
sys 0m2.146s
It never hurts to check. I generally keep an eye out for suspicious behavior. I also have root run chkrootkit as above nightly just for grins. If it finds anything, It'll notify me. For a while there was a Redhat process that triggered false positives. Thankfully that is no longer the case.
In general, because of the way that Linux partitions user and admin space, you aren't much at risk, and since there are very few programs that you need to be root to run them, it's not a big deal. The biggest problem from a historical basis with Windows is that there was a huge base of (broken IMO) programs that senselessly required Admin access to run. This caused users to just make their user account administrator, which is extremely dangerous and stupid.
That, and the fact that Microsoft still thinks it is a good idea for files to execute based on the name of the file. (again, stupid).
Then you get things like microsoft "helping" you out by doing incredibly dumb things, like autorunning programs on CDs.
No operating system is fool-proof of course, because fools are sometimes such clever bastards. On the other hand, both OSX and Linux are safer by default, because they have essentially always been multi-user systems. with all the design consierations that implies. Having more than one user on a computer is something that was essentially bolted on years afterwards, and the need for backwards compatibility caused some serious compromises to be made in design decisions.