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AST-17: Network Diagrams & Data Flow Diagrams (DFDs)

AST 10 — Critical Identify

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)
Framework Mapping Values
AICPA TSC 2017:2022 (used for SOC 2) (source) C1.1-POF1 CC2.1 CC2.1-POF2 CC2.1-POF5
CIS CSC 8.1 3.8 12.4
CIS CSC 8.1 IG2 3.8 12.4
CIS CSC 8.1 IG3 3.8 12.4
COBIT 2019 APO14.08
COSO 2013 13.0
CSA CCM 4.1.0 DSP-05 I&S-08
CSA IoT SCF 2 DAT-03
GovRAMP PL-02 SA-04(01) SA-04(02)
GovRAMP Low PL-02
GovRAMP Low+ PL-02
GovRAMP Moderate PL-02 SA-04(01)
GovRAMP High PL-02 SA-04(01) SA-04(02)
IEC 62443-2-1 2024 CM 1.2
ISO 27002 2022 5.9 8.20
ISO 27017 2015 8.1.1
ISO 27018 2025 5.9 8.20
MPA Content Security Program 5.3.1 TS-2.2
NIST 800-37 R2 TASK P-11
NIST 800-53 R4 PL-2 SA-5(1) SA-5(2) SA-5(3) SA-5(4)
NIST 800-53 R5.2 PL-02 SA-04(01) SA-04(02)
NIST 800-53B R5 (low) (source) PL-02
NIST 800-53B R5 (moderate) (source) PL-02 SA-04(01) SA-04(02)
NIST 800-53B R5 (high) (source) PL-02 SA-04(01) SA-04(02)
NIST 800-53B R5 (privacy) (source) PL-02
NIST 800-82 R3 PL-02 SA-04(01) SA-04(02)
NIST 800-82 R3 LOW OT Overlay PL-02
NIST 800-82 R3 MODERATE OT Overlay PL-02 SA-04(01) SA-04(02)
NIST 800-82 R3 HIGH OT Overlay PL-02 SA-04(01) SA-04(02)
NIST 800-161 R1 PL-2
NIST 800-161 R1 C-SCRM Baseline PL-2
NIST 800-161 R1 Flow Down PL-2
NIST 800-161 R1 Level 3 PL-2
NIST 800-171 R3 (source) 03.01.03 03.04.11.a 03.04.11.b
NIST 800-171A R3 (source) A.03.01.03[02] A.03.04.11.a[02] A.03.04.11.b[01] A.03.04.11.b[02]
NIST 800-172 R3 03.01.14E
NIST 800-172A R3 A.03.01.14E.ODP[02]
NIST 800-207 NIST Tenet 1
NIST CSF 2.0 (source) ID.AM-03
NIST Privacy Framework 1.0 ID.IM-P7 ID.IM-P8
PCI DSS 4.0.1 (source) 1.2.3 1.2.4
PCI DSS 4.0.1 SAQ A-EP (source) 1.2.3 1.2.4
PCI DSS 4.0.1 SAQ B-IP (source) 1.2.3
PCI DSS 4.0.1 SAQ D Merchant (source) 1.2.3 1.2.4
PCI DSS 4.0.1 SAQ D Service Provider (source) 1.2.3 1.2.4
SCF DPMP 2026 5.2
SPARTA 4.0 CM0022
SWIFT CSF 2025 2.4
US (19)
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

  1. AST-17_A01 sensitive / regulated data flows are identified and documented.
  2. AST-17_A02 a Data Flow Diagram (DFD) exists for each type of sensitive / regulated data that is stored, processed and/or transmitted.
  3. AST-17_A03 a process exists to review DFDs for accuracy per an organization-defined frequency.
  4. 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.
  5. 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.
  6. 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.
  7. AST-17_A07 a process exists to review network diagrams for accuracy per an organization-defined frequency.
  8. 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

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