Best attack strategy for a Red Team?

[Scott <opiesan () gmail com>]

Howdy folks!

I'm part of a Red Team for the Mid-Atlantic region CCDC competition
(Collegiate Cyber Defense Competition). There are some pretty talented
folks on the team and I'm arguably the least experienced (for now).
The short version explanation is that teams of college students are
tasked with operating and defending a "corporate" network of systems
ranging from web, email, DB, MS Domain servers, VoIP, and normal
workstations. They have to patch a wide variety of holes while keeping
designated services available for scoring. The team with the most
uptime wins. Meanwhile, the red team is busy attacking these services
along with anything else we can get into and create havoc for the
student teams.

My question to all of you is what you would recommend for an attack
strategy here. In previous competitions it's been challenging to know
where to start as there are many options. Should I find a hole and dig
in with backdoors, create new user accounts, take over the admin
accounts and lock out the student teams??? Technically the red team is
supposed to bring down or deny access to the services the students are
scored on (primary objective). There's always more going than that
however. I'd like to stay focused when we go into the 3 day event this
month so I need a plan.

How would you do it if you didn't know more than possibly what types
of systems you'll find on the target networks? Thanks.

Scott