CFG-03: Least Functionality
Mechanisms exist to configure Technology Assets, Applications and/or Services (TAAS) to provide only essential capabilities by specifically prohibiting or restricting the use of ports, protocols, and/or services.
Control Question: Does the organization configure systems to provide only essential capabilities by specifically prohibiting or restricting the use of ports, protocols, and/or services?
General (48)
| Framework | Mapping Values |
|---|---|
| AICPA TSC 2017:2022 (used for SOC 2) (source) | CC5.2-POF3 CC6.1-POF7 CC6.7-POF1 |
| CIS CSC 8.1 | 4.0 4.6 4.8 |
| CIS CSC 8.1 IG1 | 4.6 |
| CIS CSC 8.1 IG2 | 4.6 4.8 |
| CIS CSC 8.1 IG3 | 4.6 4.8 |
| CSA CCM 4.1.0 | AIS-02 |
| GovRAMP | CM-07 |
| GovRAMP Low | CM-07 |
| GovRAMP Low+ | CM-07 |
| GovRAMP Moderate | CM-07 |
| GovRAMP High | CM-07 |
| IEC 62443-3-3 2013 | SR 7.7 |
| IEC 62443-4-2 2019 | CR 2.2 CR 7.7 |
| IMO Maritime Cyber Risk Management | 3.5.3.3 |
| ISO 27002 2022 | 8.3 8.9 8.12 |
| ISO 27017 2015 | 9.4.1 |
| ISO 27018 2025 | 8.9 8.12 |
| MITRE ATT&CK 16 | T1003 T1003.001 T1003.002 T1003.005 T1008 T1011 T1011.001 T1020.001 T1021 T1021.001 T1021.002 T1021.003 T1021.005 T1021.006 T1021.008 T1027 T1036 T1036.005 T1036.007 T1036.008 T1037 T1037.001 T1040 T1046 T1047 T1048 T1048.001 T1048.002 T1048.003 T1052 T1052.001 T1053 T1053.002 T1053.005 T1059 T1059.005 T1059.007 T1059.009 T1059.010 T1068 T1071 T1071.001 T1071.002 T1071.003 T1071.004 T1072 T1078 T1078.004 T1080 T1087 T1087.001 T1087.002 T1090 T1090.001 T1090.002 T1090.003 T1092 T1095 T1098 T1098.001 T1098.004 T1098.007 T1102 T1102.001 T1102.002 T1102.003 T1104 T1105 T1106 T1112 T1127 T1127.002 T1129 T1133 T1135 T1136 T1136.002 T1136.003 T1176 T1187 T1190 T1195 T1195.001 T1195.002 T1197 T1199 T1204 T1204.001 T1204.002 T1204.003 T1205 T1205.001 T1210 T1213 T1213.001 T1213.002 T1213.004 T1213.005 T1216 T1216.001 T1216.002 T1218 T1218.001 T1218.002 T1218.003 T1218.004 T1218.005 T1218.007 T1218.008 T1218.009 T1218.012 T1218.013 T1218.014 T1218.015 T1219 T1220 T1221 T1482 T1484 T1489 T1490 T1498 T1498.001 T1498.002 T1499 T1499.001 T1499.002 T1499.003 T1499.004 T1505.004 T1525 T1530 T1537 T1542.004 T1542.005 T1543 T1546.002 T1546.006 T1546.008 T1546.009 T1546.010 T1547.004 T1547.006 T1547.007 T1547.009 T1548 T1548.001 T1548.003 T1548.004 T1548.006 T1552 T1552.003 T1552.005 T1552.007 T1553 T1553.001 T1553.003 T1553.004 T1553.005 T1553.006 T1555.004 T1555.006 T1556 T1556.002 T1556.008 T1556.009 T1557 T1557.001 T1557.002 T1557.003 T1559 T1559.002 T1559.003 T1562 T1562.001 T1562.002 T1562.003 T1562.004 T1562.006 T1562.009 T1562.010 T1563 T1563.001 T1563.002 T1564.002 T1564.003 T1564.006 T1564.008 T1564.009 T1565 T1565.003 T1569 T1569.002 T1570 T1571 T1572 T1573 T1573.001 T1573.002 T1574 T1574.001 T1574.006 T1574.007 T1574.008 T1574.009 T1574.012 T1574.014 T1590.002 T1599 T1599.001 T1601 T1601.001 T1601.002 T1602 T1602.001 T1602.002 T1609 T1610 T1611 T1612 T1613 T1622 T1647 T1648 T1653 |
| MPA Content Security Program 5.3.1 | TS-2.8 TS-8.2 |
| NIST 800-53 R4 | CM-7 |
| NIST 800-53 R5.2 | CM-07 |
| NIST 800-53B R5 (low) (source) | CM-07 |
| NIST 800-53B R5 (moderate) (source) | CM-07 |
| NIST 800-53B R5 (high) (source) | CM-07 |
| NIST 800-82 R3 | CM-07 |
| NIST 800-82 R3 LOW OT Overlay | CM-07 |
| NIST 800-82 R3 MODERATE OT Overlay | CM-07 |
| NIST 800-82 R3 HIGH OT Overlay | CM-07 |
| NIST 800-161 R1 | CM-7 |
| NIST 800-161 R1 C-SCRM Baseline | CM-7 |
| NIST 800-161 R1 Flow Down | CM-7 |
| NIST 800-161 R1 Level 3 | CM-7 |
| NIST 800-171 R2 (source) | 3.4.6 |
| NIST 800-171 R3 (source) | 03.04.02.a 03.04.06.a 03.04.06.b 03.04.06.d 03.04.08.a |
| NIST 800-171A (source) | 3.4.6[a] 3.4.6[b] 3.4.7[g] 3.4.7[j] |
| NIST 800-171A R3 (source) | A.03.04.02.ODP[01] A.03.04.02.a[01] A.03.04.06.a A.03.04.06.b[01] A.03.04.06.b[02] A.03.04.06.b[03] A.03.04.06.b[04] A.03.04.06.b[05] A.03.04.06.d A.03.04.08.a |
| NIST CSF 2.0 (source) | PR.PS-05 |
| NIST Privacy Framework 1.0 | PR.PT-P2 |
| OWASP Top 10 2025 | A05:2025 |
| PCI DSS 4.0.1 (source) | 1.2.5 1.2.6 1.4 1.4.1 1.4.2 2.2.4 |
| PCI DSS 4.0.1 SAQ A-EP (source) | 1.2.5 1.2.6 1.4.1 1.4.2 2.2.4 |
| PCI DSS 4.0.1 SAQ B-IP (source) | 1.2.5 1.2.6 1.4.2 |
| PCI DSS 4.0.1 SAQ C (source) | 2.2.4 |
| PCI DSS 4.0.1 SAQ C-VT (source) | 2.2.4 |
| PCI DSS 4.0.1 SAQ D Merchant (source) | 1.2.5 1.2.6 1.4.1 1.4.2 2.2.4 |
| PCI DSS 4.0.1 SAQ D Service Provider (source) | 1.2.5 1.2.6 1.4.1 1.4.2 2.2.4 |
| SPARTA 4.0 | CM0047 |
| SWIFT CSF 2025 | 2.3 2.10 |
US (16)
| Framework | Mapping Values |
|---|---|
| USA Federal CMS MARS-E 2.0 | CM-7 CM-7.a CM-7.b CM-7-IS.1 |
| USA Federal CISA CPG 2022 | 2.W |
| USA Federal C2M2 2.1 | ARCHITECTURE-3d |
| USA Federal CMMC 2.0 Level 2 | CML2.-3.4.6 |
| USA Federal CJIS Security Policy 6.0 | CM-7 |
| USA Federal FFIEC ITEH 2016 | II.C.10.b |
| USA Federal FedRAMP R5 (low) | CM-07 |
| USA Federal FedRAMP R5 (moderate) | CM-07 |
| USA Federal FedRAMP R5 (high) | CM-07 |
| USA Federal FedRAMP R5 (LI-SaaS) | CM-07 |
| USA Federal IRS 1075 2021 | CM-7 CM-7(IRS-Defined) |
| USA Federal NERC CIP 2024 | CIP-007-6 1.1 |
| USA California CCPA 2025 | 7123(c)(11) |
| USA Texas DIR SCSC 2.2 2025 | CM-07 |
| USA Texas TX-RAMP Level 1 | CM-07 |
| USA Texas TX-RAMP Level 2 | CM-07 |
EMEA (10)
| Framework | Mapping Values |
|---|---|
| EMEA Germany C5 2026 | COS-02.01B.2 |
| EMEA Spain CCN-STIC 825 | op.exp.2 op.exp.3 |
| EMEA Spain Royal Decree 311 2022 | Article 20(c) |
| EMEA EU NIS2 Annex 2024 | 6.7.2(f) |
| EMEA UK Cyber Essentials 3.3 | 2-BP3 |
| EMEA UK DEFSTAN 05-138 2024 | 2204 2430 2507 |
| EMEA UK DEFSTAN 05-138 - L1 2024 | 2204 2507 |
| EMEA UK DEFSTAN 05-138 - L2 2024 | 2204 2430 2507 |
| EMEA UK DEFSTAN 05-138 - L3 2024 | 2204 2430 2507 |
| EMEA Saudi Arabia OTCC-1 2022 | 2-4-1-14 |
APAC (9)
| Framework | Mapping Values |
|---|---|
| APAC Australia IoT Code of Practice 2024 | 6.0 |
| APAC Australia Essential 8 2024 | ISM-1175 ISM-1883 |
| APAC Australia ISM June 2026 | ISM-0385 ISM-1006 ISM-1175 ISM-1311 ISM-1312 ISM-1392 ISM-1470 ISM-1479 ISM-1883 |
| APAC India RBI Digital Payments 2021 | 9.0 |
| APAC India SEBI CSCRF 2024 | PR.IP.S1 |
| APAC Malaysia RMiT 2025 | A2-C10(b) A2-C10(c) A2-C10(d) A2-C10(f) A2-NC3 A2-NC4 A2-NC5 A2-NC7 A2-NC8 |
| APAC New Zealand NZISM 3.9 | 18.1.15.C.01 18.1.15.C.02 18.1.15.C.04 |
| APAC Singapore CCOP CII 2026 | 5.9.2 5.9.2(c) 5.9.2(d) 5.12.7 12.5.1 12.5.2 |
| APAC Singapore MAS TRM 2021 | 11.2.6 |
Americas (2)
| Framework | Mapping Values |
|---|---|
| Americas Canada ITSP-10-171 2025 | 03.04.02.A 03.04.06.A 03.04.06.B 03.04.06.D 03.04.08.A |
| Americas Canada OSFI B-13 2022 | 3.2.8 |
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). ▪ The restrictiveness of the SBCs are commensurate with the criticality of the TAAS and/or sensitivity of the data being protected, in accordance with applicable laws, regulations and frameworks.
Level 3 — Well Defined
Configuration Management (CFG) 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 CFG 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 CFG domain capabilities are well-documented and kept current by process owners. ▪ A configuration management team, or similar function, is appropriately staffed and supported to implement and maintain CFG domain capabilities. ▪ Technology is leveraged to enhance the efficiency and accuracy of configuration management operations (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 CFG 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 configure systems to provide only essential capabilities by specifically prohibiting or restricting the use of ports, protocols, and/or services.
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
- CFG-03_A01 configuration settings for the system that reflect the most restrictive mode consistent with operational requirements are defined (e.g., principle of least functionality).
- CFG-03_A02 systems are configured to provide only the defined essential capabilities, where unnecessary or nonsecure functions, ports, protocols, connections, and services are disabled or removed.
- CFG-03_A03 functions to be prohibited or restricted are defined.
- CFG-03_A04 ports to be prohibited or restricted are defined.
- CFG-03_A05 protocols to be prohibited or restricted are defined.
- CFG-03_A06 software to be prohibited or restricted is defined.
- CFG-03_A07 services to be prohibited or restricted are defined.
- CFG-03_A08 the use of organization-defined functions is prohibited or restricted.
- CFG-03_A09 the use of organization-defined ports is prohibited or restricted.
- CFG-03_A10 the use of organization-defined protocols is prohibited or restricted.
- CFG-03_A11 the use of organization-defined software is prohibited or restricted.
- CFG-03_A12 the use of organization-defined services is prohibited or restricted.
- CFG-03_A13 configuration settings for the system reflect the most restrictive mode consistent with operational requirements are defined.
- CFG-03_A14 unnecessary or nonsecure functions, ports, protocols, connections, and services are disabled or removed.
Evidence Requirements
- E-AST-13 Secure Baseline Configurations - Cloud-Based Services
-
Documented evidence of secure baseline configurations for all deployed types of cloud-based services or applications.
Asset Management - E-AST-14 Secure Baseline Configurations - Databases
-
Documented evidence of secure baseline configurations for all deployed types of databases.
Asset Management - E-AST-15 Secure Baseline Configurations - Embedded Technologies
-
Documented evidence of secure baseline configurations for all deployed types of embedded technologies.
Asset Management - E-AST-16 Secure Baseline Configurations - Major Applications
-
Documented evidence of secure baseline configurations for all deployed types of major applications.
Asset Management - E-AST-17 Secure Baseline Configurations - Minor Applications
-
Documented evidence of secure baseline configurations for all deployed types of minor applications.
Asset Management - E-AST-18 Secure Baseline Configurations - Mobile Devices
-
Documented evidence of secure baseline configurations for all deployed types of mobile devices.
Asset Management - E-AST-19 Secure Baseline Configurations - Network Devices
-
Documented evidence of secure baseline configurations for all deployed types of network devices.
Asset Management - E-AST-20 Secure Baseline Configurations - Server Class Systems
-
Documented evidence of secure baseline configurations for all deployed types of server-class operating systems.
Asset Management - E-AST-21 Secure Baseline Configurations - Workstation Class Systems
-
Documented evidence of secure baseline configurations for all deployed types of workstation-class operating systems.
Asset Management
Technology Recommendations
Micro/Small
- Secure Baseline Configurations (SBC)
- Defense Information Security Agency (DISA) Secure Technology Implementation Guides (STIGs)
- Center for Internet Security (CIS) Benchmarks
- Original Equipment Manufacturer (OEM) security guides
Small
- Secure Baseline Configurations (SBC)
- Defense Information Security Agency (DISA) Secure Technology Implementation Guides (STIGs)
- Center for Internet Security (CIS) Benchmarks
- Original Equipment Manufacturer (OEM) security guides
Medium
- Secure Baseline Configurations (SBC)
- Defense Information Security Agency (DISA) Secure Technology Implementation Guides (STIGs)
- Center for Internet Security (CIS) Benchmarks
- Original Equipment Manufacturer (OEM) security guides
Large
- Secure Baseline Configurations (SBC)
- Defense Information Security Agency (DISA) Secure Technology Implementation Guides (STIGs)
- Center for Internet Security (CIS) Benchmarks
- Original Equipment Manufacturer (OEM) security guides
Enterprise
- Secure Baseline Configurations (SBC)
- Defense Information Security Agency (DISA) Secure Technology Implementation Guides (STIGs)
- Center for Internet Security (CIS) Benchmarks
- Original Equipment Manufacturer (OEM) security guides