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NET-05: Interconnection Security Agreements (ISAs)

NET 9 — Critical Protect

Mechanisms exist to authorize connections from systems to other systems using Interconnection Security Agreements (ISAs), or similar methods, that document, for each interconnection: (1) Interface characteristics; (2) Security, compliance and resilience requirements; and; (3) The nature of the information communicated.

Control Question: Does the organization authorize connections from systems to other systems using Interconnection Security Agreements (ISAs), or similar methods, that document, for each interconnection: (1) Interface characteristics; (2) Security, compliance and resilience requirements; and; (3) The nature of the information communicated?

General (26)
Framework Mapping Values
GovRAMP CA-03
GovRAMP Low CA-03
GovRAMP Low+ CA-03
GovRAMP Moderate CA-03
GovRAMP High CA-03
IEC 62443-2-1 2024 NET 1.2
MITRE ATT&CK 16 T1020.001 T1041 T1048 T1048.002 T1048.003 T1078 T1567
NIST 800-53 R4 CA-3 CA-3(1) CA-3(2)
NIST 800-53 R5.2 CA-03 SC-07(25) SC-07(26)
NIST 800-53B R5 (low) (source) CA-03
NIST 800-53B R5 (moderate) (source) CA-03
NIST 800-53B R5 (high) (source) CA-03
NIST 800-82 R3 CA-03 SC-07(25) SC-07(26)
NIST 800-82 R3 LOW OT Overlay CA-03
NIST 800-82 R3 MODERATE OT Overlay CA-03
NIST 800-82 R3 HIGH OT Overlay CA-03
NIST 800-161 R1 CA-3
NIST 800-161 R1 C-SCRM Baseline CA-3
NIST 800-161 R1 Flow Down CA-3
NIST 800-161 R1 Level 3 CA-3
NIST 800-171 R2 (source) NFO - CA-3
NIST 800-171 R3 (source) 03.01.03 03.01.20.c.02 03.12.05.a 03.12.05.b
NIST 800-171A R3 (source) A.03.01.03[02] A.03.01.20.c.02 A.03.12.05.ODP[01] A.03.12.05.ODP[02] A.03.12.05.a[01] A.03.12.05.a[02] A.03.12.05.b[01] A.03.12.05.b[02] A.03.12.05.b[03] A.03.12.05.c[01] A.03.12.05.c[02]
NIST 800-172 R3 03.12.04E
NIST 800-172A R3 DS-A.03.12.04E.a A.03.12.04E.ODP[01] DS-A.03.12.04E.b[01] DS-A.03.12.04E.b[02] DS-A.03.12.04E.b[03] A.03.12.04E.ODP[02] DS-A.03.12.04E.d
SWIFT CSF 2025 2.4
US (13)
EMEA (3)
Framework Mapping Values
EMEA Germany C5 2026 COS-02.01B.6 COS-04.02B
EMEA Spain Royal Decree 311 2022 Article 23
EMEA EU DORA RTS 2024 Article 13.1(m)
APAC (1)
Framework Mapping Values
APAC India RBI Digital Payments 2021 8.d
Americas (1)
Framework Mapping Values
Americas Canada ITSP-10-171 2025 03.01.03 03.01.20.C.02 03.12.05.A 03.12.05.B

Capability Maturity Model

Level 0 — Not Performed

Practices are non-existent, based on the inability to demonstrate an implemented and operational capability. A reasonable person would conclude the control is not being performed.

Level 1 — Performed Informally

Network Security (NET) domain capabilities are ad hoc and inconsistent. Capability criteria associated with this control may include: ▪ Policies, standards & procedures associated with NET domain capabilities provide limited coverage due to the depth and breadth of the existing documentation. ▪ Network security-related activities are decentralized (e.g., a localized/regionalized function) and uses non-standardized methods to implement secure, resilient and compliant practices.

Level 2 — Planned & Tracked

Network Security (NET) capabilities are requirements-driven, but are not standardized across the entity (e.g., local/regional level consistency). Capability criteria associated with this control reasonably expect the following criteria to exist: ▪ Policies and standards associated with NET domain capabilities are formally documented and centrally-managed by the entity. ▪ Standardized Operating Procedures (SOP) associated with NET domain capabilities are documented and maintained by process owners. ▪ IT and/or cybersecurity personnel work with business stakeholders and process owners to appropriately scope and reasonably implement cybersecurity and data protection controls associated with NET domain capabilities to address applicable statutory, regulatory and/or contractual requirements for Technology Assets, Applications, Services and/or Data (TAASD). ▪ Network security-related controls are primarily administrative and preventative in nature (e.g., policies, standards and procedures & guidelines). ▪ Network security management may be a defined function (e.g., team or department) or assigned as an additional duty to existing IT and/or cybersecurity personnel. ▪ IT personnel define secure networking practices to protect the Confidentiality, Integrity, Availability and Safety (CIAS) of the organization's TAASD. ▪ Secure Baseline Configurations (SBC) enforce the principles of least privileges and least functionality for boundary protection technologies.

Level 3 — Well Defined

Network Security (NET) capabilities are standardized across the entity for applicability to People, Processes, Technologies, Data and/or Facilities (PPTDF) to ensure consistency for Technology Assets, Applications, Services and/or Data (TAASD). Capability criteria associated with this control reasonably expect the following criteria to exist: ▪ Policies and standards associated with NET domain capabilities are formally documented and centrally-managed by the entity's Governance, Risk & Compliance (GRC) team, or similar function. ▪ Standardized Operating Procedures (SOP) associated with NET domain capabilities are well-documented and kept current by process owners. ▪ A network security management team, or similar function, is appropriately staffed and supported to implement and maintain NET domain capabilities. ▪ Technology is leveraged to enhance the efficiency and accuracy of network security operations (e.g., network management solution and log aggregator). ▪ The entity's Governance, Risk & Compliance (GRC) team, or similar function, works with business stakeholders and process owners to appropriately scope and reasonably implement cybersecurity and data protection controls associated with NET domain capabilities to address Minimum Compliance Requirements (MCR) (e.g., applicable statutory, regulatory and/or contractual requirements) and Discretionary Security Requirements (DSR) (e.g., entity-required controls). ▪ Secure Baseline Configurations (SBC) enforce the principles of least privileges and least functionality for boundary protection technologies. ▪ An implemented and operational capability exists to authorize connections from systems to other systems using Interconnection Security Agreements (ISAs), or similar methods, that document, for each interconnection: (1) Interface characteristics; (2) Security, compliance and resilience requirements; and; (3) The nature of the information communicated.

Level 4 — Quantitatively Controlled

Utilize SCR-CMM Level 3 criteria definitions: ▪ There are no defined Level 4 criteria, since it is reasonable to assume a quantitatively-controlled process is not necessary to operationalize this control. ▪ While it may be possible to develop “metrics-driven” capabilities for this control, the criteria would be organization-specific to define.

Level 5 — Continuously Improving

Utilize SCR-CMM Level 3 or Level 4 (if available) criteria definitions: ▪ There are no defined Level 5 criteria, since it is reasonable to assume a continuously-improving process is not necessary to operationalize this control. ▪ Level 5 capabilities should be considered “world-class” where the control builds on Level 4 capabilities, but are continuously improving through Artificial Intelligence (AI) and/or Machine Learning (ML) technologies. ▪ While it may be possible to develop responsive capabilities for this control through the use of AI and/or ML technologies, the criteria would be organization-specific to define.

Assessment Objectives

  1. NET-05_A01 the type of agreement used to approve and manage the exchange of information is defined (e.g., interconnection security agreements, information exchange security agreements, memoranda of understanding or agreement, service level agreements, user agreements, non-disclosure agreements or organization-defined type of agreements).
  2. NET-05_A02 security requirements for each system are documented as part of the exchange agreements.
  3. NET-05_A03 controls are documented as part of each exchange agreement.
  4. NET-05_A04 the frequency at which to review and update agreements is defined.
  5. NET-05_A05 the exchange of sensitive / regulated data between the system and other systems is approved using organization-defined values.
  6. NET-05_A06 the exchange of sensitive / regulated data between the system and other systems is managed using organization-defined values.
  7. NET-05_A07 interface characteristics for each system are documented as part of the exchange agreements.
  8. NET-05_A08 responsibilities for each system are documented as part of the exchange agreements.
  9. NET-05_A09 the impact level of the information communicated is documented as part of each exchange agreement.
  10. NET-05_A10 exchange agreements are reviewed per an organization-defined frequency.
  11. NET-05_A11 exchange agreements are updated per an organization-defined frequency.
  12. NET-05_A12 systems are prohibited from directly connecting to an external network is defined.
  13. NET-05_A13 the boundary protection device required for a direct connection to an external network is defined.
  14. NET-05_A14 the direct connection of systems to an external network without the use of boundary protection device is prohibited.
  15. NET-05_A15 the direct connection of classified national security system to an external network without the use of an organization-defined boundary protection device is prohibited.
  16. NET-05_A16 approved authorizations are enforced for controlling the flow of CUI between connected systems.
  17. NET-05_A17 one or more of the following PARAMETER VALUES are selected: {interconnection security agreements; information exchange security agreements; memoranda of understanding or agreement; service-level agreements; user agreements; non-disclosure agreements; other types of agreements}.
  18. NET-05_A18 the exchange of CUI between the system and other systems is approved using <A.03.12.05.ODP[01]: SELECTED PARAMETER VALUES>.
  19. NET-05_A19 the exchange of CUI between the system and other systems is managed using <A.03.12.05.ODP[01]: SELECTED PARAMETER VALUES>.
  20. NET-05_A20 exchange agreements are reviewed <A.03.12.05.ODP[02]: frequency>.
  21. NET-05_A21 exchange agreements are updated <A.03.12.05.ODP[02]: frequency>.

Evidence Requirements

E-NET-06 Authorized Network Connections

Documented evidence of third-party Technology Assets, Applications and/or Services (TAAS) authorized to connect to organizational TAAS, including remote access authorizations.

Network Security
E-TPM-07 System Connection or Processing Agreements

Documented evidence of system connection or processing agreements.

Third-Party Management

Technology Recommendations

Micro/Small

  • Interconnection Security Agreement (ISA)
  • Information Exchange Security Agreements (IESA)
  • Memoranda of Understanding (MOU) / Agreement (MOA)

Small

  • Interconnection Security Agreement (ISA)
  • Information Exchange Security Agreements (IESA)
  • Memoranda of Understanding (MOU) / Agreement (MOA)

Medium

  • Interconnection Security Agreement (ISA)
  • Information Exchange Security Agreements (IESA)
  • Memoranda of Understanding (MOU) / Agreement (MOA)

Large

  • Interconnection Security Agreement (ISA)
  • Information Exchange Security Agreements (IESA)
  • Memoranda of Understanding (MOU) / Agreement (MOA)

Enterprise

  • Interconnection Security Agreement (ISA)
  • Information Exchange Security Agreements (IESA)
  • Memoranda of Understanding (MOU) / Agreement (MOA)

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