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NIST SP 800-53 Rev. 5 · CA-3

Information Exchange

US National Institute of Standards and Technology (NIST) · cited in 14 of our lessons

Explanation

What it asks for. Information exchanges between the system and other systems must be approved and managed using agreements such as interconnection security agreements or service level agreements, which document interface characteristics, security and privacy requirements, controls, responsibilities and the impact level of the information, and are reviewed and updated periodically.

In practice. This means an inventory of system connections and data exchanges with partners and suppliers, each with an owner and an agreement or documented terms covering security responsibilities. API integrations, file transfers and network links should all be included. Auditors look for the interconnection inventory, signed agreements and evidence of periodic review.

Common gaps. API and SaaS integrations are often set up by business teams without formal agreements or security review. Old connections remain open after the business relationship ends.

Open SP 800-53 at NIST
The official text
a. Approve and manage the exchange of information between the system and other systems using [Selection: interconnection security agreements; information exchange security agreements; memoranda of understanding or agreement; service level agreements; user agreements; non-disclosure agreements; {{ insert: param, ca-03_odp.02 }} ]; b. Document, as part of each exchange agreement, the interface characteristics, security and privacy requirements, controls, and responsibilities for each system, and the impact level of the information communicated; and c. Review and update the agreements [Assignment: organization-defined frequency]. Discussion: System information exchange requirements apply to information exchanges between two or more systems. System information exchanges include connections via leased lines or virtual private networks, connections to internet service providers, database sharing or exchanges of database transaction information, connections and exchanges with cloud services, exchanges via web-based services, or exchanges of files via file transfer protocols, network protocols (e.g., IPv4, IPv6), email, or other organization-to-organization communications. Organizations consider the risk related to new or increased threats that may be introduced when systems exchange information with other systems that may have different security and privacy requirements and controls. This includes systems within the same organization and systems that are external to the organization. A joint authorization of the systems exchanging information, as described in [CA-6(1)](#ca-6.1) or [CA-6(2)](#ca-6.2) , may help to communicate and reduce risk. Authorizing officials determine the risk associated with system information exchange and the controls needed for appropriate risk mitigation. The types of agreements selected are based on factors such as the impact level of the information being exchanged, the relationship between the organizations exchanging information (e.g., government to government, government to business, business to business, government or business to service provider, government or business to individual), or the level of access to the organizational system by users of the other system. If systems that exchange information have the same authorizing official, organizations need not develop agreements. Instead, the interface characteristics between the systems (e.g., how the information is being exchanged. how the information is protected) are described in the respective security and privacy plans. If the systems that exchange information have different authorizing officials within the same organization, the organizations can develop agreements or provide the same information that would be provided in the appropriate agreement type from [CA-3a](#ca-3_smt.a) in the respective security and privacy plans for the systems. Organizations may incorporate agreement information into formal contracts, especially for information exchanges established between federal agencies and nonfederal organizations (including service providers, contractors, system developers, and system integrators). Risk considerations include systems that share the same networks.

From NIST SP 800-53 Rev. 5, a work of the US government in the public domain.

Lessons that cite it

Real incidents where this item mattered: the latest 12 of 14.