PR.PT-4: Communications and control networks are protected

Automatically terminate a user session after [Assignment: organization-defined conditions, or trigger events requiring session disconnect].

Establish and document usage restrictions, configuration/connection requirements, and implementation guidance for each type of remote access allowed; and Authorize each type of remote access to the system prior to allowing such connections.

Establish configuration requirements, connection requirements, and implementation guidance for each type of wireless access; and Authorize each type of wireless access to the system prior to allowing such connections.

Establish alternate telecommunications services, including necessary agreements to permit the resumption of [Assignment: organization-defined system operations] for essential mission and business functions within [Assignment: organization-defined time period] when the primary telecommunications capabilities are unavailable at either the primary or alternate processing or storage sites.

[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].

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…

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

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].

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…

Request and perform data origin authentication and data integrity verification on the name/address resolution responses the system receives from authoritative sources.

Ensure the systems that collectively provide name/address resolution service for an organization are fault-tolerant and implement internal and external role separation.

Protect the authenticity of communications sessions.

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.

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].

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

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

Establishing usage restrictions and configuration/connection requirements for wireless access to the system provides criteria for organizations to support wireless access authorization decisions. Such restrictions and requirements reduce the susceptibility to unauthorized access to the system through wireless technologies. Wireless networks use authentication protocols which provide credential protection and mutual authentication. [SP 800-97] provide guidance on…

Organizations authenticate individuals and devices to help protect wireless access to the system. Special attention is given to the wide variety of devices that are part of the Internet of Things with potential wireless access to organizational systems. See [NIST CRYPTO].

Communications can be monitored, controlled, and protected at boundary components and by restricting or prohibiting interfaces in organizational systems. Boundary components include gateways, routers, firewalls, guards, network-based malicious code analysis and virtualization systems, or encrypted tunnels implemented within a system security architecture (e.g., routers protecting firewalls or application gateways residing on protected subnetworks). Restricting or…

Organizations apply systems security engineering principles to new development systems or systems undergoing major upgrades. For legacy systems, organizations apply systems security engineering principles to system upgrades and modifications to the extent feasible, given the current state of hardware, software, and firmware components within those systems. The application of systems security engineering concepts and principles…

Subnetworks that are physically or logically separated from internal networks are referred to as demilitarized zones (DMZs). DMZs are typically implemented with boundary control devices and techniques that include routers, gateways, firewalls, virtualization, or cloud-based technologies. [SP 800-41] provides guidance on firewalls and firewall policy. [SP 800-125B] provides guidance on security for virtualization technologies.

This requirement applies to inbound and outbound network communications traffic at the system boundary and at identified points within the system. A deny-all, permit-by-exception network communications traffic policy ensures that only those connections which are essential and approved are allowed.

Split tunneling might be desirable by remote users to communicate with local system resources such as printers or file servers. However, split tunneling allows unauthorized external connections, making the system more vulnerable to attack and to exfiltration of organizational information. This requirement is implemented in remote devices (e.g., notebook computers, smart phones, and tablets) through…

Authenticity protection includes protecting against man-in-the-middle attacks, session hijacking, and the insertion of false information into communications sessions. This requirement addresses communications protection at the session versus packet level (e.g., sessions in service-oriented architectures providing web-based services) and establishes grounds for confidence at both ends of communications sessions in ongoing identities of other parties and…