The operating system is the backbone of a computer. It directs, manages and controls all the various applications installed on the hardware. The OS also processes the input/output data between the user and the computer.
Today's popular operating systems, Microsoft's Windows, Mac OS X of Apple and Chrome of Google cannot be said to be completely safe. Each of them has its own vulnerabilities. Not one is foolproof. A user of any of these softwares could be secure for a period of time, but for how long depends on the complacency of the vendor company.
Why do you think Microsoft is releasing security updates for their Windows softwares almost every month? Because it needs to be protected from those malicious writers who is always on the lookout for any loopholes in the system which they could exploit.
Just a couple of days ago Microsoft announced that they will be doing patches this September to fix 13 vulnerabilities.
Now, you might contend that Linux, or Chrome, or Mac OS X is safer and that Windows are more prone to attack by hackers. I don't think so. The only reason why Microsoft software is the target of so many viruses and malwares is because it is so widely used.
Any operating system is impervious to risks. Apple's Mac computers which have a reputation of being largely untouched by threats also have its own flaws.
A recent news on Apple is about the patching of three gaping holes on Safari 5.0.2 and Safari 4.1.2. These browsers are available for Mac OS X versions 10.5 and 10.6 and on Mac OS X version 10.4. These vulnerabilities on the browsers potentially put web surfers at risks of drive-by download attacks.
Even the Department of Home Security (DHS) knows the high-risk involved when they were alerted by the failure to keep its own systems upto date with the latest software patches. The vulnerabilities on their system was discovered not have been fixed when auditors working for the DHS inspector general ran a sweep of US-CERT using vulnerability scanner Nessus.