If you have Do-It-Yourself security, you're on your own.
If the apps are written to use
J2EE's standard container security system, all you need is a single signon security provider such as CAS.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.