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SC-8: Transmission Confidentiality and Integrity

An OSCAL Control

Statement

    • Protect the of transmitted information.

        • Guidance:

          For each instance of data in transit, confidentiality AND integrity should be through cryptography as specified in SC-8 (1), physical means as specified in SC-8 (5), or in combination.

          For clarity, this control applies to all data in transit. Examples include the following data flows:

          • Crossing the system boundary
          • Between compute instances - including containers
          • From a compute instance to storage
          • Replication between availability zones
          • Transmission of backups to storage
          • From a load balancer to a compute instance
          • Flows from management tools required for their work - e.g. log collection, scanning, etc.

          The following applies only when choosing SC-8 (5) in lieu of SC-8 (1).

          FedRAMP-Defined Assignment / Selection Parameters

          SC-8 (5)-1 [a hardened or alarmed carrier Protective Distribution System (PDS) when outside of Controlled Access Area (CAA)]

          SC-8 (5)-2 [prevent unauthorized disclosure of information AND detect changes to information]

        • Guidance:

          SC-8 (5) applies when physical protection has been selected as the method to protect confidentiality and integrity. For physical protection, data in transit must be in either a Controlled Access Area (CAA), or a Hardened or alarmed PDS.

          Hardened or alarmed PDS: Shall be as defined in SECTION X - CATEGORY 2 PDS INSTALLATION GUIDANCE of CNSSI No.7003, titled PROTECTED DISTRIBUTION SYSTEMS (PDS). Per the CNSSI No. 7003 Section VIII, PDS must originate and terminate in a Controlled Access Area (CAA).

          Controlled Access Area (CAA): Data will be considered physically protected, and in a CAA if it meets Section 2.3 of the DHS's Recommended Practice: Improving Industrial Control System Cybersecurity with Defense-in-Depth Strategies. CSPs can meet Section 2.3 of the DHS' recommended practice by satisfactory implementation of the following controls PE-2 (1), PE-2 (2), PE-2 (3), PE-3 (2), PE-3 (3), PE-6 (2), and PE-6 (3).

          Note: When selecting SC-8 (5), the above SC-8(5), and the above referenced PE controls must be added to the SSP.

          CNSSI No.7003 can be accessed here:

          https://www.dcsa.mil/Portals/91/documents/ctp/nao/CNSSI_7003_PDS_September_2015.pdf

          DHS Recommended Practice: Improving Industrial Control System Cybersecurity with Defense-in-Depth Strategies can be accessed here:

          https://us-cert.cisa.gov/sites/default/files/FactSheets/NCCIC%20ICS_FactSheet_Defense_in_Depth_Strategies_S508C.pdf