IS LINUX SECURE?

The big question and, a very broad question too. The truth is nothing is secure. It is a broad trade off. There is a tradeoff between convenience and security, When I talk convenience I am also talking about  the ease of use. For instance, it would be very convenient if users don't have to identify themselves before users have access to the system, but that wouldn't be very secure. This is just one simplistic example of a tradeoff. you will often be making tradeoff decisions depending on the severity or probability of the risk you are trying to mitigate.  Cost consideration, effectiveness of counter performance as well as system performance will all be considered before you make a tradeoff. In general Linux is secure, but, only as secure as its users, and system administrators make it and, allow it to be. Linux can be made into a very unsecure platform. for example a user can change a file that contains sensitive data on the file such that anyone can read it, system administrators can change all the files on the system such as anyone can modify them, or worst, user can use  easy to guess passwords, data could be transmitted to in the clear, malicious software can be installed on the system. To sum it up, just because you are using Linux, doesn't mean you are secure. Just because it is more secure than windows doesn't necessarily mean you don't maintain the security protocols.