SC: System and Communications Protection

OT Tailoring Considerations

The use of cryptography is determined after careful consideration of the security needs and the potential ramifications on system performance. For example, the organization considers whether latency induced from the use of cryptography would adversely impact the operational performance of the OT. While the legacy devices commonly found within OT often lack direct support for cryptographic functions, compensating controls (e.g., encapsulations) may be used to meet the intent of the control.

When the OT cannot support the specific system and communications protection requirements of a control, the organization employs compensating controls in accordance with the general tailoring guidance. Examples of compensating controls are given with each control as appropriate.

Controls

SC-1: Policy and Procedures

Baseline(s):

  • Low
  • Moderate
  • High
  • OT Low (SP 800-82r3)
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Develop, document, and disseminate to [Assignment: organization-defined personnel or roles]: [Assignment (one or more): organization-level, mission/business-process-level, system-level] system and communications protection policy that: Addresses purpose, scope, roles, responsibilities, management commitment, coordination among organizational entities, and compliance; and Is consistent with applicable laws, executive orders, directives, regulations, policies, standards, and guidelines; and Procedures to facilitate the…

SC-5: Denial-of-service Protection

Baseline(s):

  • Low
  • Moderate
  • High
  • OT Low (SP 800-82r3)
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

[Assignment: protect against, limit] the effects of the following types of denial-of-service events: [Assignment: organization-defined types of denial-of-service events] ; and Employ the following controls to achieve the denial-of-service objective: [Assignment: organization-defined controls by type of denial-of-service event].

SC-6: Resource Availability

Baseline(s):

(Not part of any baseline)

Protect the availability of resources by allocating [Assignment: organization-defined resources] by [Assignment (one or more): priority, quota, [Assignment: organization-defined controls] ].

SC-7: Boundary Protection

Baseline(s):

  • Low
  • Moderate
  • High
  • OT Low (SP 800-82r3)
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Monitor and control communications at the external managed interfaces to the system and at key internal managed interfaces within the system; Implement subnetworks for publicly accessible system components that are [Assignment: physically, logically] separated from internal organizational networks; and Connect to external networks or systems only through managed interfaces consisting of boundary protection devices arranged…

SC-10: Network Disconnect

Baseline(s):

  • Moderate
  • High

Terminate the network connection associated with a communications session at the end of the session or after [Assignment: organization-defined time period] of inactivity.

SC-11: Trusted Path

Baseline(s):

(Not part of any baseline)

Provide a [Assignment: physically, logically] isolated trusted communications path for communications between the user and the trusted components of the system; and Permit users to invoke the trusted communications path for communications between the user and the following security functions of the system, including at a minimum, authentication and re-authentication: [Assignment: organization-defined security functions].

SC-12: Cryptographic Key Establishment and Management

Baseline(s):

  • Low
  • Moderate
  • High
  • OT Low (SP 800-82r3)
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Establish and manage cryptographic keys when cryptography is employed within the system in accordance with the following key management requirements: [Assignment: organization-defined requirements].

SC-13: Cryptographic Protection

Baseline(s):

  • Low
  • Moderate
  • High
  • OT Low (SP 800-82r3)
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Determine the [Assignment: organization-defined cryptographic uses] ; and Implement the following types of cryptography required for each specified cryptographic use: [Assignment: organization-defined types of cryptography].

SC-15: Collaborative Computing Devices and Applications

Baseline(s):

  • Low
  • Moderate
  • High
  • OT Low (SP 800-82r3)
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Prohibit remote activation of collaborative computing devices and applications with the following exceptions: [Assignment: organization-defined exceptions where remote activation is to be allowed] ; and Provide an explicit indication of use to users physically present at the devices.

SC-17: Public Key Infrastructure Certificates

Baseline(s):

  • Moderate
  • High
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Issue public key certificates under an [Assignment: organization-defined certificate policy] or obtain public key certificates from an approved service provider; and Include only approved trust anchors in trust stores or certificate stores managed by the organization.

SC-18: Mobile Code

Baseline(s):

  • Moderate
  • High
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Define acceptable and unacceptable mobile code and mobile code technologies; and Authorize, monitor, and control the use of mobile code within the system.

SC-20: Secure Name/Address Resolution Service (Authoritative Source)

Baseline(s):

  • Low
  • Moderate
  • High
  • OT Low (SP 800-82r3)
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Provide additional data origin authentication and integrity verification artifacts along with the authoritative name resolution data the system returns in response to external name/address resolution queries; and Provide the means to indicate the security status of child zones and (if the child supports secure resolution services) to enable verification of a chain of trust among…

SC-23: Session Authenticity

Baseline(s):

  • Moderate
  • High
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Protect the authenticity of communications sessions.

SC-24: Fail in Known State

Baseline(s):

  • High
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Fail to a [Assignment: organization-defined known system state] for the following failures on the indicated components while preserving [Assignment: organization-defined system state information] in failure: [Assignment: organization-defined types of system failures on system components].

SC-25: Thin Nodes

Baseline(s):

(Not part of any baseline)

Employ minimal functionality and information storage on the following system components: [Assignment: organization-defined system components].

SC-26: Decoys

Baseline(s):

(Not part of any baseline)

Include components within organizational systems specifically designed to be the target of malicious attacks for detecting, deflecting, and analyzing such attacks.

SC-27: Platform-independent Applications

Baseline(s):

(Not part of any baseline)

Include within organizational systems the following platform independent applications: [Assignment: organization-defined platform-independent applications].

SC-28: Protection of Information at Rest

Baseline(s):

  • Moderate
  • High
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Protect the [Assignment (one or more): confidentiality, integrity] of the following information at rest: [Assignment: organization-defined information at rest].

SC-29: Heterogeneity

Baseline(s):

(Not part of any baseline)

Employ a diverse set of information technologies for the following system components in the implementation of the system: [Assignment: organization-defined system components].

SC-30: Concealment and Misdirection

Baseline(s):

(Not part of any baseline)

Employ the following concealment and misdirection techniques for [Assignment: organization-defined systems] at [Assignment: organization-defined time periods] to confuse and mislead adversaries: [Assignment: organization-defined concealment and misdirection techniques].

SC-31: Covert Channel Analysis

Baseline(s):

(Not part of any baseline)

Perform a covert channel analysis to identify those aspects of communications within the system that are potential avenues for covert [Assignment (one or more): storage, timing] channels; and Estimate the maximum bandwidth of those channels.

SC-32: System Partitioning

Baseline(s):

(Not part of any baseline)

Partition the system into [Assignment: organization-defined system components] residing in separate [Assignment: physical, logical] domains or environments based on [Assignment: organization-defined circumstances for the physical or logical separation of components].

SC-34: Non-modifiable Executable Programs

Baseline(s):

(Not part of any baseline)

For [Assignment: organization-defined system components] , load and execute: The operating environment from hardware-enforced, read-only media; and The following applications from hardware-enforced, read-only media: [Assignment: organization-defined applications].

SC-36: Distributed Processing and Storage

Baseline(s):

(Not part of any baseline)

Distribute the following processing and storage components across multiple [Assignment: physical locations, logical domains]: [Assignment: organization-defined processing and storage components].

SC-37: Out-of-band Channels

Baseline(s):

(Not part of any baseline)

Employ the following out-of-band channels for the physical delivery or electronic transmission of [Assignment: organization-defined information, system components, or devices] to [Assignment: organization-defined individuals or systems]: [Assignment: organization-defined out-of-band channels].

SC-38: Operations Security

Baseline(s):

(Not part of any baseline)

Employ the following operations security controls to protect key organizational information throughout the system development life cycle: [Assignment: organization-defined operations security controls].

SC-39: Process Isolation

Baseline(s):

  • Low
  • Moderate
  • High
  • OT Low (SP 800-82r3)
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Maintain a separate execution domain for each executing system process.

SC-40: Wireless Link Protection

Baseline(s):

(Not part of any baseline)

Protect external and internal [Assignment: organization-defined wireless links] from the following signal parameter attacks: [Assignment: organization-defined types of signal parameter attacks or references to sources for such attacks].

SC-41: Port and I/O Device Access

Baseline(s):

  • OT Low (SP 800-82r3)
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

[Assignment: physically, logically] disable or remove [Assignment: organization-defined connection ports or input/output devices] on the following systems or system components: [Assignment: organization-defined systems or system components].

SC-42: Sensor Capability and Data

Baseline(s):

(Not part of any baseline)

Prohibit [Assignment (one or more): the use of devices possessing [Assignment: organization-defined environmental sensing capabilities] in [Assignment: organization-defined facilities, areas, or systems] , the remote activation of environmental sensing capabilities on organizational systems or system components with the following exceptions: [Assignment: organization-defined exceptions where remote activation of sensors is allowed] ] ; and Provide an…

SC-43: Usage Restrictions

Baseline(s):

(Not part of any baseline)

Establish usage restrictions and implementation guidelines for the following system components: [Assignment: organization-defined components] ; and Authorize, monitor, and control the use of such components within the system.

SC-44: Detonation Chambers

Baseline(s):

(Not part of any baseline)

Employ a detonation chamber capability within [Assignment: organization-defined system, system component, or location].

SC-45: System Time Synchronization

Baseline(s):

  • OT Low (SP 800-82r3)
  • OT Moderate (SP 800-82r3)
  • OT High (SP 800-82r3)

Synchronize system clocks within and between systems and system components.

SC-46: Cross Domain Policy Enforcement

Baseline(s):

(Not part of any baseline)

Implement a policy enforcement mechanism [Assignment: physically, logically] between the physical and/or network interfaces for the connecting security domains.

SC-47: Alternate Communications Paths

Baseline(s):

  • OT High (SP 800-82r3)

Establish [Assignment: organization-defined alternate communication paths] for system operations organizational command and control.

SC-48: Sensor Relocation

Baseline(s):

(Not part of any baseline)

Relocate [Assignment: organization-defined sensors and monitoring capabilities] to [Assignment: organization-defined locations] under the following conditions or circumstances: [Assignment: organization-defined conditions or circumstances].

SC-51: Hardware-based Protection

Baseline(s):

(Not part of any baseline)

Employ hardware-based, write-protect for [Assignment: organization-defined system firmware components] ; and Implement specific procedures for [Assignment: organization-defined authorized individuals] to manually disable hardware write-protect for firmware modifications and re-enable the write-protect prior to returning to operational mode.