NET-40.1: Electronic Messaging
Mechanisms exist to protect the confidentiality, integrity and availability of electronic messaging communications.
Renumbered: Formerly NET-13 in SCF 2025.4.
Control Question: Does the organization protect the confidentiality, integrity and availability of electronic messaging communications?
General (9)
| Framework | Mapping Values |
|---|---|
| AICPA TSC 2017:2022 (used for SOC 2) (source) | CC6.6 CC6.6-POF2 CC6.7 |
| ISO 27002 2022 | 5.14 |
| ISO 27017 2015 | 13.2.1 13.2.3 |
| ISO 27018 2025 | 5.14 |
| NIST 800-53 R4 | SC-8(3) SC-19 |
| NIST 800-53 R5.2 | SC-08(03) |
| NIST 800-82 R3 | SC-08(03) |
| NIST 800-171 R2 (source) | 3.13.14 |
| NIST 800-171A (source) | 3.13.14[a] 3.13.14[b] |
US (3)
| Framework | Mapping Values |
|---|---|
| USA Federal CMS MARS-E 2.0 | SC-ACA-1 SC-ACA-1-IS.a SC-ACA-2 SC-ACA-2.a SC-ACA-2-IS.1 SC-ACA-2-IS.1.a SC-ACA-2-IS.1.b SC-ACA-2-IS.1.c |
| USA Federal CISA CPG 2022 | 2.M |
| USA Federal CMMC 2.0 Level 2 | SCL2.-3.13.14 |
EMEA (2)
| Framework | Mapping Values |
|---|---|
| EMEA Spain CCN-STIC 825 | mp.s.1 |
| EMEA Saudi Arabia IoT CGIoT-1 2024 | 2-3-1 2-3-2 |
APAC (3)
| Framework | Mapping Values |
|---|---|
| APAC Australia ISM June 2026 | ISM-0264 ISM-0267 ISM-0269 ISM-0270 ISM-0271 ISM-0272 ISM-0490 ISM-0494 ISM-0496 ISM-0498 ISM-0565 ISM-0569 ISM-0570 ISM-0571 ISM-0572 ISM-0574 ISM-0861 ISM-0998 ISM-0999 ISM-1000 ISM-1023 ISM-1024 ISM-1026 ISM-1027 ISM-1089 ISM-1151 ISM-1183 ISM-1540 ISM-1589 |
| APAC Japan ISMAP | 13.2.2.12 13.2.2.13 13.2.3 13.2.3.1 13.2.3.2 13.2.3.3 13.2.3.4 13.2.3.5 13.2.3.6 13.2.3.7.P |
| APAC New Zealand NZISM 3.9 | 15.1.7.C.01 15.1.8.C.01 15.1.8.C.02 15.1.9.C.01 15.1.10.C.01 15.1.10.C.02 15.1.10.C.03 15.1.11.C.01 15.1.11.C.02 15.1.11.C.03 15.1.12.C.01 15.1.13.C.01 15.1.14.C.01 15.1.15.C.01 15.1.16.C.01 15.1.17.C.01 15.1.18.C.01 15.1.19.C.01 15.1.19.C.02 15.1.20.C.01 17.6.6.C.01 17.6.7.C.01 |
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. ▪ Network communications containing sensitive/regulated data are protected using a cryptographic mechanism to prevent unauthorized disclosure of information while in transit (e.g., SSH, TLS and VPN).
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 protect the confidentiality, integrity and availability of electronic messaging communications.
Level 4 — Quantitatively Controlled
Network Security (NET) capabilities, in addition to being standardized across the entity and centrally managed to ensure consistency across Technology Assets, Applications, Services and/or Data (TAASD), efforts are metrics driven to provide sufficient insight for decision makers to predict optimal performance, ensure continued operations and/or identify areas for improvement. Capability criteria associated with this control reasonably expect the following criteria to exist: ▪ Applicable SCR-CMM Level 3 (Well Defined) capabilities are implemented and operational. ▪ Metrics reporting includes quantitative analysis of Key Performance Indicators (KPIs). ▪ Metrics reporting includes quantitative analysis of Key Risk Indicators (KRIs). ▪ Scope of metrics, KPIs and KRIs covers organization-wide cybersecurity and data protection controls, including functions performed by third-parties. ▪ Organizational leadership maintains a formal process to objectively review and respond to metrics, KPIs and KRIs (e.g., monthly or quarterly review). ▪ Based on metrics analysis, process improvement recommendations are submitted for review and are handled in accordance with change control processes. ▪ Business and technical stakeholders are involved in reviewing and approving proposed changes to evolve capabilities.
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
- NET-40.1_A01 cryptographic mechanisms are implemented to protect message externals unless otherwise protected by alternative physical controls.
- NET-40.1_A02 alternative physical controls to protect message externals are defined.
- NET-40.1_A03 use of Voice over Internet Protocol (VoIP) technologies is controlled.
- NET-40.1_A04 use of Voice over Internet Protocol (VoIP) technologies is monitored.
Technology Recommendations
Micro/Small
- Acceptable Use Policy (AUP)
- Data Loss Prevention (DLP)
Small
- Acceptable Use Policy (AUP)
- Data Loss Prevention (DLP)
Medium
- Acceptable Use Policy (AUP)
- Data Loss Prevention (DLP)
Large
- Acceptable Use Policy (AUP)
- Data Loss Prevention (DLP)
Enterprise
- Acceptable Use Policy (AUP)
- Data Loss Prevention (DLP)