NIST 800-53 REV 5 • SYSTEM AND COMMUNICATIONS PROTECTION
SC-7(26) — Classified National Security System Connections
Prohibit the direct connection of a classified national security system to an external network without the use of {{ insert: param, sc-07.26_odp }}.
CMMC Practice Mapping
No direct CMMC mapping
NIST 800-171 Mapping
No direct NIST 800-171 mapping
Related Controls
No related controls listed
Supplemental Guidance
A direct connection is a dedicated physical or virtual connection between two or more systems. Organizations typically do not have complete control over external networks, including the Internet. Boundary protection devices (e.g., firewalls, gateways, and routers) mediate communications and information flows between classified national security systems and external networks. In addition, approved boundary protection devices (typically managed interface or cross-domain systems) provide information flow enforcement from systems to external networks.
Practitioner Notes
Connections involving classified national security systems have the strictest requirements — typically requiring NSA-approved encryption and cross-domain solutions.
Example 1: Use an NSA-approved cross-domain solution (CDS) for any data exchange between classified and unclassified networks. The CDS inspects and sanitizes all data transfers according to content filtering rules approved by the designated approving authority.
Example 2: Classified network connections must use NSA Type 1 encryption devices. Document these connections in your System Security Plan and get explicit authorization from the appropriate government authority before establishing any new connection.