Through the recesses of time, and watching Software Development sprout into unique languages, and easier ways to create programs, online interaction, and reports, as well as database technology moving from old structure to a more parent/child relationship, the machines that process these languages are commonly using architecture which is easily hack-able. So, security is always a moving target. Hackers figure out ways to get into your systems with a click of the mouse.
The humble view of comparing the legacy Mainframe Computers to the newer architectures, leaves an impression in my mind that the Mainframes have never been hacked. As an expert developing COBOL code in the past, there was never such a thing as hacking an IBM Mainframe Computer. That is why I believe Mainframes aren't going anywhere ever. Government agencies, banks, and other business organizations still use these types of machines with its solid architecture.
It would be a lot more difficult to hack or drop a virus on a Mainframe Computer. Unlike Windows, Mainframe programs can’t create copies of itself, or have free range to corrupt Application systems. With Mainframes there are several stages of approval with batch jobs, and online processing. For example, CA7 is a job scheduler on a Mainframe, it is effective, and does not allow any program to run by design. Also, there is a service called RACF, which assigns and manages all user access, it does not allow unauthorized users to perform activities without authority. There are many other facts about Mainframes, which are not ideal for the hacker or viruses.
My personal recommendation is that mission critical data & systems ought to be kept on architectures like the Mainframes, and not be accessible to the internet for obvious and well-publicized reasons.
Written by Carmen Y. Burns