Okay something is fishy here. Several terabytes of bandwidth doesn't just happen unnoticed. Either this occurred over many months in which time routine checks and sweeps would have found the data leak or this was a massive burst in a short period of time which would have set off a host of alarms.
The DOD systems have high speed connections but still this is kind of like relocating an elephant using a bicycle. This screams inside job.
Just following the example set by the Clintons.
Just received in an email;
http://www.cnn.com/2009/US/04/21/pentagon.hacked/index.html