The tl;dr of this part is that I recommend once you learn of the MACCDC theme, look for related open-source linux distros (virtual appliances).  Download a couple and mess around with them.  Who knows, you might get lucky and pick the actual distro used in the qualifiers.  At best, it will save you time once the competition starts and at worst you'll still learn to navigate your way around a linux box if you already aren't familiar.

The Sahana Eden distro has webmin running by default, which coincidentally was a monitored service by the scorebot.  Webmin, if you're not familiar (because I'd never seen it before!) is a web-based linux administration portal.  By default, it was only accessible from internal addresses so you could only access it on the local host itself or from another asset.  I debated trying to modify the configuration files to make it externally accessible, but since our Active Directory guy had his system set already I used his box to look at the webmin portal for anything useful.  One less external vector for the red team, right?  Since I'd never seen it, I originally assumed it was the web-app itself.  Once I figured out that it wasn't, I was able to re-focus my attention on getting Sahana Eden up and running.