NET-03.13: Split Tunneling
Mechanisms exist to prevent split tunneling for remote devices unless the split tunnel is securely provisioned using organization-defined safeguards.
Renumbered: Formerly CFG-03.4 in SCF 2025.4.
Control Question: Does the organization prevent split tunneling for remote devices unless the split tunnel is securely provisioned using organization-defined safeguards?
General (18)
| Framework | Mapping Values |
|---|---|
| GovRAMP | SC-07(07) |
| GovRAMP Low+ | SC-07(07) |
| GovRAMP Moderate | SC-07(07) |
| GovRAMP High | SC-07(07) |
| NIST 800-53 R4 | SC-7(7) |
| NIST 800-53 R5.2 | SC-07(07) |
| NIST 800-53B R5 (moderate) (source) | SC-07(07) |
| NIST 800-53B R5 (high) (source) | SC-07(07) |
| NIST 800-82 R3 | SC-07(07) |
| NIST 800-82 R3 MODERATE OT Overlay | SC-07(07) |
| NIST 800-82 R3 HIGH OT Overlay | SC-07(07) |
| NIST 800-171 R2 (source) | 3.13.7 |
| NIST 800-171A (source) | 3.13.7 |
| PCI DSS 4.0.1 (source) | 1.5.1 |
| PCI DSS 4.0.1 SAQ A-EP (source) | 1.5.1 |
| PCI DSS 4.0.1 SAQ C-VT (source) | 1.5.1 |
| PCI DSS 4.0.1 SAQ D Merchant (source) | 1.5.1 |
| PCI DSS 4.0.1 SAQ D Service Provider (source) | 1.5.1 |
US (6)
| Framework | Mapping Values |
|---|---|
| USA Federal CMS MARS-E 2.0 | SC-7(7) |
| USA Federal CMMC 2.0 Level 2 | SCL2.-3.13.7 |
| USA Federal CJIS Security Policy 6.0 | SC-7(7) |
| USA Federal FedRAMP R5 (moderate) | SC-07(07) |
| USA Federal FedRAMP R5 (high) | SC-07(07) |
| USA Federal IRS 1075 2021 | SC-7(CE-7) SC-7(CE-7).a SC-7(CE-7).b SC-7(CE-7).b.1 SC-7(CE-7).b.2 SC-7(CE-7).b.3 SC-7(CE-7).c SC-7(CE-7).c.1 SC-7(CE-7).c.2 SC-7(CE-7).c.3 SC-7(CE-7).c.4 |
EMEA (4)
| Framework | Mapping Values |
|---|---|
| EMEA UK DEFSTAN 05-138 2024 | 2305 |
| EMEA UK DEFSTAN 05-138 - L1 2024 | 2305 |
| EMEA UK DEFSTAN 05-138 - L2 2024 | 2305 |
| EMEA UK DEFSTAN 05-138 - L3 2024 | 2305 |
APAC (2)
| Framework | Mapping Values |
|---|---|
| APAC Australia ISM June 2026 | ISM-0705 |
| APAC New Zealand NZISM 3.9 | 18.7.14.C.01 18.7.14.C.02 |
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
Configuration Management (CFG) domain capabilities are ad hoc and inconsistent. Capability criteria associated with this control may include: ▪ Policies, standards & procedures associated with CFG domain capabilities provide limited coverage due to the depth and breadth of the existing documentation. ▪ Configuration management-related activities are decentralized (e.g., a localized/regionalized function) and uses non-standardized methods to implement secure, resilient and compliant practices. ▪ Configurations mostly conform to industry-recognized standards for hardening (e.g., DISA STIGs, CIS Benchmarks or OEM security guides).
Level 2 — Planned & Tracked
Configuration Management (CFG) 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 CFG domain capabilities are formally documented and centrally-managed by the entity. ▪ Standardized Operating Procedures (SOP) associated with CFG 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 CFG domain capabilities to address applicable statutory, regulatory and/or contractual requirements for Technology Assets, Applications, Services and/or Data (TAASD). ▪ Configuration management-related controls are primarily administrative and preventative in nature (e.g., policies, standards and procedures & guidelines). ▪ Configuration management may be a defined function (e.g., team or department) or assigned as an additional duty to existing IT and/or cybersecurity personnel. ▪ Secure Baseline Configurations (SBC) are used to configure Technology Assets, Applications and/or Services (TAAS) according to the principles of least functionality and least privilege, mostly conforming to industry-recognized standards for hardening (e.g., DISA STIGs, CIS Benchmarks or OEM security guides).
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 prevent split tunneling for remote devices unless the split tunnel is securely provisioned using organization-defined safeguards.
Level 4 — Quantitatively Controlled
Configuration Management (CFG) 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
Configuration Management (CFG) 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. ▪ Based on predictive analysis, process improvements are implemented according to “continuous improvement” practices that affect process changes. ▪ Stakeholders make time-sensitive decisions to support operational efficiency, which may include automated remediation actions via Artificial Intelligence (AI) or Machine Learning (ML) technologies.
Assessment Objectives
- NET-03.13_A01 safeguards to securely provision split tunneling are defined.
- NET-03.13_A02 remote devices are prevented from simultaneously establishing non-remote connections with the system and communicating via some other connection to resources in external networks (e.g., split tunneling).
Technology Recommendations
Micro/Small
- Secure Baseline Configurations (SBC)
Small
- Secure Baseline Configurations (SBC)
Medium
- Secure Baseline Configurations (SBC)
Large
- Secure Baseline Configurations (SBC)
Enterprise
- Secure Baseline Configurations (SBC)