SIPRNet

networkingsecurity

The US Department of Defense network for information classified up to secret, physically separate from both the unclassified network and the public internet.

The middle tier of the three, and the one whose failure mode is best documented. The 2010 disclosure of a very large volume of diplomatic cables did not involve breaching the network's separation from the internet: it involved someone with legitimate access to the network copying material they were entitled to reach. That distinction is the whole lesson. Physical separation defends comprehensively against outsiders and not at all against insiders, and a network whose perimeter is a wire that does not exist can still be emptied by anybody already inside it. The response was not more separation but more granular access control, monitoring of bulk access patterns, and restrictions on removable media - all of which are the ordinary tools of an enterprise, applied late. Any organisation that describes its most sensitive system as safe because it is not connected to anything should read that sequence carefully.

Also known as: sipr, secret internet protocol router network

← All glossary entries