Which INFOCON level allows for non-essential networks to be taken offline?

INFOCON, or Information Operations Condition, is a system used by the U.S. Department of Defense to indicate the current level of threat to information systems and networks. Each level corresponds to specific operational conditions and response measures.

At INFOCON 2, there is a heightened state of alert because there is a significant threat to information systems, and adversaries may be actively targeting these systems. As a precautionary measure, to mitigate the potential for damage caused by these threats, the directive to take non-essential networks offline is implemented. This action helps safeguard critical systems and ensures that essential operations can continue without the interference or risk associated with compromised networks.

In contrast, INFOCON 3 indicates a general threat where monitoring and defensive measures are heightened but does not necessitate the offline status of non-essential networks. INFOCON 4 reflects a more normal operating environment with lower threat levels, while INFOCON 5 indicates a routine readiness posture with minimal concern for cyber threats. Therefore, only at INFOCON 2 is the practice of taking non-essential networks offline warranted to protect vital resources.