veitchk wrote:
Look at getting a quality security system in place that lets you know anyone attempting to access the camera, microphone and other things. The bit defender product works well for me.
Third party anti-virus and security software is not needed on a Mac and usually causes more problems than it solves plus it impacts system performance. These forums are filled with people solving their macOS problems by uninstalling this type of software.
The best thing a person can do is run the latest version of macOS and the latest version of all their third party apps. Running an OS or software that is no longer receiving security updates is always risky and is discouraged if you are fearful of the system becoming vulnerable. Plus later versions of macOS have a lot more security features to restrict apps from using or accessing various items including the Camera and Mic (much like on the iPhone).
Otherwise the easiest way to block the camera is by putting a piece of Post-It Note or tape over the camera. For older unsupported versions of macOS it would be better to find an app that specializes in just controlling or disabling these items (Camera, Mic, etc.) as that will cause much fewer issues than an anti-virus app and third party security software.
As always if you practice safe computing habits such as don't download or install unknown apps (and limit third party apps in general) so you greatly reduce your risk. Plus only get third party apps from the App Store (still be careful here what you install as those apps still may not be 100% safe) or from the developer's own website since any other source may include other surprises in their downloads. Plus be careful of the websites you visit and the links you click on including links in emails even from family & friends.