"The Open Web Application Security Project® (OWASP) is a nonprofit foundation that works to improve the security of software. Through community-led open-source software projects, hundreds of local chapters worldwide, tens of thousands of members, and leading educational and training conferences, the OWASP Foundation is the source for developers and technologists to secure the web." - OWASP
Even though we're not using this book to teach you to become software engineers, the OWASP project has some cool insights into the common security vulnerabilities on the Internet. This is referred to as the "OWASP Ten Top".
The OWASP Top Ten can be read about here. I won't list them here as they change. Not often, but they do change, so the course might offer misleading guidance to future readers.
This top ten list of vulnerabilities are what hackers are using to breach online systems. If you look through the list, you'll see things like "Broken Access Control", "Security Misconfiguration", and more. These are complex topics that each could have their own course dedicated to them.
At this point in time have a read of the list and if something takes you interest, read up about it. Just remember to stay focused and come back to the course in good time.
Now let's look at virtualisation so we can understand how the world changed and how we got to what we call "public Cloud" today.