SC-7(5): Deny by Default – Allow by Exception
Control Family:
Parent Control:
Threats Addressed:
Baselines:
- Moderate
- High
Previous Version:
- NIST Special Publication 800-53 Revision 4:
- SC-7(5): Deny By Default / Allow By Exception
Incorporates the following control from the previous version: CA-3(5): Restrictions On External System Connections.
Control Statement
Deny network communications traffic by default and allow network communications traffic by exception [Assignment (one or more): at managed interfaces, for [Assignment: organization-defined systems] ].
Supplemental Guidance
Denying by default and allowing by exception applies to inbound and outbound network communications traffic. A deny-all, permit-by-exception network communications traffic policy ensures that only those system connections that are essential and approved are allowed. Deny by default, allow by exception also applies to a system that is connected to an external system.