So, one kind of vulnerability that a website might be susceptible to could be tested by doing the following:

1. Log in as User A
2. Navigate to a page & copy the URL from the address bar
3. Logout
4. Log in as User B
5. Paste the URL into the address bar and see information for User A

(p.s. what is the official name for something like this?)

What I am wondering if there is a good blog post or website out there that would cover this kind and other kinds of vulnerabilities, explaining how they can be tested.

Thank you.