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NET-06.1: Security Management Subnets

NET 9 — Critical Protect

Mechanisms exist to implement security management subnets to isolate security tools and support components from other internal system components by implementing separate subnetworks with managed interfaces to other components of the system.

Control Question: Does the organization implement security management subnets to isolate security tools and support components from other internal system components by implementing separate subnetworks with managed interfaces to other components of the system?

General (23)
Framework Mapping Values
AICPA TSC 2017:2022 (used for SOC 2) (source) CC6.1
CSA IoT SCF 2 SAP-01
GovRAMP SC-07(13)
GovRAMP Low+ SC-07(13)
GovRAMP Moderate SC-07(13)
GovRAMP High SC-07(13)
IEC 62443-3-3 2013 SR 5.1 RE 2
ISO 27002 2022 8.22
ISO 27017 2015 13.1.3
ISO 27018 2025 8.22
NIST 800-53 R4 SC-7(13)
NIST 800-53 R5.2 SC-07(13) SC-07(29)
NIST 800-82 R3 SC-07(13) SC-07(29)
NIST 800-82 R3 LOW OT Overlay SC-07(29)
NIST 800-82 R3 MODERATE OT Overlay SC-07(29)
NIST 800-82 R3 HIGH OT Overlay SC-07(29)
NIST 800-160 Vol2 R1 SC-07(13) SC-07(29)
NIST 800-161 R1 SC-7(13)
NIST 800-161 R1 Flow Down SC-7(13)
NIST 800-161 R1 Level 3 SC-7(13)
NIST 800-172 R3 03.13.09E 03.13.15E
NIST 800-172A R3 DS-A.03.13.09E DS-A.03.13.15E
SWIFT CSF 2025 1.1
US (2)
Framework Mapping Values
USA Federal CMS MARS-E 2.0 SC-7(13)
USA California CCPA 2025 7123(c)(5)(B) 7123(c)(10)
EMEA (2)
Framework Mapping Values
EMEA Spain CCN-STIC 825 op.ext.4 mp.com.4
EMEA EU DORA RTS 2024 Article 13.1(c)
APAC (2)
Framework Mapping Values
APAC Australia ISM June 2026 ISM-1385 ISM-1750
APAC Japan ISMAP 13.1.4.P

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. ▪ Processing and storage of service location, including a managed security zone to house cybersecurity and data protection tools.

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 implement security management subnets to isolate security tools and support components from other internal system components by implementing separate subnetworks with managed interfaces to other components of the system.

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

  1. NET-06.1_A01 cybersecurity tools, mechanisms and support components to be isolated from other internal system components are defined.
  2. NET-06.1_A02 cybersecurity tools, mechanisms and support components are isolated from other internal system components by implementing physically separate subnetworks with managed interfaces to other components of the system.
  3. NET-06.1_A03 security management subnets are logically isolated.
  4. NET-06.1_A04 security management subnet system components and functions to be isolated are defined.
  5. NET-06.1_A05 organization-defined criteria are used to isolate security management subnets.
  6. NET-06.1_A06 physical isolation techniques are defined.
  7. NET-06.1_A07 logical isolation techniques are defined.
  8. NET-06.1_A08 physical isolation techniques and/or organization-defined logical isolation techniques are employed in organizational systems and system components.

Technology Recommendations

Micro/Small

  • Separate VLAN or network for management interfaces of firewall/switches where supported

Small

  • Dedicated management VLAN for security tools and infrastructure devices

Medium

  • Separate management network or VLAN for security management

Large

  • Dedicated security management subnet
  • Out-of-band management access controls

Enterprise

  • Enterprise out-of-band management network
  • Dedicated jump servers
  • Privileged access workstations (PAW)

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