Implies they were using DHCP on their classified network or the operator had permission to change the NIC IP or configure a second NIC. Either way it’s poor security. My sympathy to the families of the affected IT department.
I thought that Classified Systems were supposed to be on a separate physical network too? I assume that some guy on the off-shifts decided to surf some porn at work and only could get into the one PC. Maybe, the Chinese decided that they were smarter than us and didn’t need two separate computers like we use.