One of the greatest strengths of Linux over other OS is the centralized software and update management tools that come built in. This means that whenever there is an update to any of the packages or softwares you have installed, you are sure to not miss it. This alone goes a long way to improve the security of a Linux system.

However, I noted a common misconception (I believe it's not just one person who has this notion) that every software in the Ubuntu repository is checked for malicious code by Canonical before it is uploaded. This I believe is not what happens.

rest here