AST-17: Network Diagrams & Data Flow Diagrams (DFDs)
Mechanisms exist to maintain network architecture diagrams that: (1) Contain sufficient detail to assess the security of the network's architecture; (2) Reflect the current architecture of the network environment; and (3) Document all sensitive and/or regulated data flows.
Renumbered: Formerly AST-04 in SCF 2025.4.
Code reused: In SCF 2025.4 and earlier, AST-17 was Prohibited Equipment & Services. That control is now AST-12.
Control Question: Does the organization maintain network architecture diagrams that: (1) Contain sufficient detail to assess the security of the network's architecture; (2) Reflect the current architecture of the network environment; and (3) Document all sensitive and/or regulated data flows?
General (48)
US (19)
| Framework | Mapping Values |
|---|---|
| USA Federal CMS MARS-E 2.0 | PL-2 SA-4(1) SA-4(2) |
| USA Federal CISA CPG 2022 | 2.P |
| USA Federal CMMC 2.0 Level 3 | AC.L3-3.1.3E |
| USA Federal DoD Zero Trust Execution Roadmap v1.1 | 4.1.1 5.1 |
| USA Federal CJIS Security Policy 6.0 | PL-2 SA-4(1) SA-4(2) |
| USA Federal FFIEC ITEH 2016 | II.C.6 |
| USA Federal FedRAMP R5 (low) | PL-02 |
| USA Federal FedRAMP R5 (moderate) | PL-02 SA-04(01) SA-04(02) |
| USA Federal FedRAMP R5 (high) | PL-02 SA-04(01) SA-04(02) |
| USA Federal FedRAMP R5 (LI-SaaS) | PL-02 |
| USA Federal IRS 1075 2021 | PL-2 SA-4(CE-1) SA-4(CE-2) |
| USA Federal 33 CFR Part 101 Subpart F | 101.650(b)(4) |
| USA Federal NRC 10 CFR 73.54 2015 | 73.54(b)(1) |
| USA Federal TSA SDP 2021-02F | III.B.1.a III.B.1.b III.B.1.c |
| USA Federal TSA / DHS 1580/82-2022-01 | III.B.1.a III.B.1.b III.B.1.c |
| USA California CCPA 2025 | 7123(c)(4)(A) |
| USA Texas DIR SCSC 2.2 2025 | PL-02 |
| USA Texas TX-RAMP Level 1 | PL-02 |
| USA Texas TX-RAMP Level 2 | PL-02 SA-04 (01) SA-04 (02) |
EMEA (12)
| Framework | Mapping Values |
|---|---|
| EMEA Germany C5 2026 | COS-07.01B COS-07.01B.1 COS-07.01B.2 COS-07.01B.3 COS-07.01B.4 COS-07.02B COS-07.03B COS-07.04B |
| EMEA Spain CCN-STIC 825 | op.pl.2 op.exp.1 op.mon.1 mp.com.1 |
| EMEA EU DORA 2023 | Article 8.4 |
| EMEA EU DORA RTS 2024 | Article 4.2(b)(viii) Article 13.1(b) |
| EMEA EU NIS2 Annex 2024 | 6.7.2(a) |
| EMEA UK CAF 4.0 | B3.a |
| EMEA UK DEFSTAN 05-138 2024 | 1203 2301 |
| EMEA UK DEFSTAN 05-138 - L1 2024 | 1203 |
| EMEA UK DEFSTAN 05-138 - L2 2024 | 1203 2301 |
| EMEA UK DEFSTAN 05-138 - L3 2024 | 1203 2301 |
| EMEA Israel CDMO 2.0 | 4.1, Stage 1 |
| EMEA Saudi Arabia OTCC-1 2022 | 2-4-1-16 |
APAC (8)
| Framework | Mapping Values |
|---|---|
| APAC Australia ISM June 2026 | ISM-0516 ISM-0518 ISM-1645 ISM-1646 |
| APAC Australia Prudential Standard CPS230 2023 | 34(a) |
| APAC India SEBI CSCRF 2024 | ID.AM.S2 |
| APAC Japan ISMAP | 4.4.4 |
| APAC Malaysia RMiT 2025 | 10.4(b) 10.41 |
| APAC New Zealand NZISM 3.9 | 18.1.9.C.02 18.1.11.C.01 18.1.12.C.01 18.1.12.C.02 |
| APAC Singapore CCOP CII 2026 | 4.1.1(e) 4.1.1(j) 12.1.1(e) 12.1.2 |
| APAC Singapore MAS TRM 2021 | 8.1.2 |
Americas (2)
| Framework | Mapping Values |
|---|---|
| Americas Argentina Reg 132 2018 | B.1.1 E.1.1-2 |
| Americas Canada ITSP-10-171 2025 | 03.01.03 03.04.11.A 03.04.11.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
SCR-CMM Level 1 criteria definitions are not available for this control: ▪ A reasonable person would conclude this control requires a structured process. ▪ At this level of maturity, the "ad hoc" nature of performing a capability informally would indicate the intent of the control is not met due to a lack of consistency and formality.
Level 2 — Planned & Tracked
Asset Management (AST) 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 AST domain capabilities are formally documented and centrally-managed by the entity. ▪ Standardized Operating Procedures (SOP) associated with AST 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 AST domain capabilities to address applicable statutory, regulatory and/or contractual requirements for Technology Assets, Applications, Services and/or Data (TAASD). ▪ Asset management-related controls are primarily administrative and preventative in nature (e.g., policies, standards and procedures & guidelines). ▪ Asset management may be a defined function (e.g., team or department) or assigned as an additional duty to existing IT and/or cybersecurity personnel. ▪ The IT department establishes, maintains and updates an inventory that contains a listing of all organizational-owned TAASD, at a minimum covering common devices (e.g., laptops, workstations and servers). ▪ IT and/or cybersecurity personnel work with process owners to generate and maintain Data Flow Diagrams (DFDs) and network diagrams to document the flow of data to create and maintain a map of systems where sensitive/regulated data is stored, transmitted or processed.
Level 3 — Well Defined
Asset Management (AST) 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 AST 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 AST domain capabilities are well-documented and kept current by process owners. ▪ An IT Asset Management (ITAM) team, or similar function, is appropriately staffed and supported to implement and maintain AST domain capabilities. ▪ Technology is leveraged to enhance the efficiency and accuracy of ITAM operations (e.g., ITAM platform, (e.g., Configuration Management Database (CMBD) Asset Management solution). ▪ 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 AST 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). ▪ An implemented and operational capability exists to maintain network architecture diagrams that: (1) Contain sufficient detail to assess the security of the network's architecture; (2) Reflect the current architecture of the network environment; and (3) Document all sensitive/regulated data flows.
Level 4 — Quantitatively Controlled
Asset Management (AST) 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
- AST-17_A01 sensitive / regulated data flows are identified and documented.
- AST-17_A02 a Data Flow Diagram (DFD) exists for each type of sensitive / regulated data that is stored, processed and/or transmitted.
- AST-17_A03 a process exists to review DFDs for accuracy per an organization-defined frequency.
- AST-17_A04 a process exists to update DFDs upon technology or business practice changes that affect where sensitive / regulated data is stored, processed and/or transmitted.
- AST-17_A05 one or more high-level network diagrams exist as a schematic to identify the logical placement of systems, applications and services at a conceptual level.
- AST-17_A06 one or more low-level network diagrams exist as a schematic to identify the detailed logical and physical placement of systems, applications and services.
- AST-17_A07 a process exists to review network diagrams for accuracy per an organization-defined frequency.
- AST-17_A08 a process exists to update network diagrams upon changes to technologies.
Evidence Requirements
- E-DCH-03 Network Diagram - Global System View (GSV)
-
Documented evidence of a high-level network diagram that provides a conceptual, logical depiction of the network(s) to describe the interconnections of the systems/applications/services, including internal and external interfaces.
Data Protection - E-DCH-04 Network Diagram - Low Level
-
Documented evidence of a low-level network diagram that provides a detailed, logical depiction of assets on the network(s).
Data Protection - E-DCH-05 Data Flow Diagram (DFD)
-
Documented evidence of a Data Flow Diagram (DFD) that accurately identifies where sensitive/regulated data is stored, transmitted and/or processed.
Data Protection
Technology Recommendations
Micro/Small
- High-Level Diagram (HLD)
- Data Flow Diagram (DFD)
- draw.io (free, https://draw.io) or Microsoft Visio
Small
- High-Level Diagram (HLD)
- Low-Level Diagram (LLD)
- Data Flow Diagram (DFD)
- draw.io (free) or Microsoft Visio
Medium
- High-Level Diagram (HLD)
- Low-Level Diagram (LLD)
- Data Flow Diagram (DFD)
- LucidChart (https://lucidchart.com) or Microsoft Visio
- Network documentation tool (e.g., NetBox, SolarWinds NTM)
Large
- High-Level Diagram (HLD)
- Low-Level Diagram (LLD)
- Data Flow Diagram (DFD)
- Network topology tool (e.g., SolarWinds Network Topology Mapper, NetBox)
- Automated network diagram updates via discovery tools
Enterprise
- High-Level Diagram (HLD)
- Low-Level Diagram (LLD)
- Data Flow Diagram (DFD)
- Enterprise network documentation platform (e.g., NetBox, SolarWinds NTM)
- Automated network discovery and diagram generation
- Diagrams integrated with CMDB and change management