Most operating systems are secure with common sense on the part of the user. But most, if not all, can become vulnerable. Apple’s rock-solid MacOS recently had a bug uncovered that allows anyone privileged access with no password, Apple has patched it, but don’t wait. Go straight to the Mac app store and update NOW. And keep your ears peeled for flaws in any other operating systems you use. If Apple can mess up, so can Windows, Linux, and Android.