SEA-26: Non-Modifiable Executable Programs
Mechanisms exist to utilize non-modifiable executable programs that load and execute the operating environment and applications from hardware-enforced, read-only media.
Renumbered: Formerly SEA-16 in SCF 2025.4.
Control Question: Does the organization utilize non-modifiable executable programs that load and execute the operating environment and applications from hardware-enforced, read-only media?
General (6)
| Framework | Mapping Values |
|---|---|
| MITRE ATT&CK 16 | T1195.003 T1218.015 T1542 T1542.001 T1542.003 T1542.004 T1542.005 T1548 T1548.004 T1553 T1553.006 T1601 T1601.001 T1601.002 T1611 |
| NIST 800-53 R4 | SC-34 |
| NIST 800-53 R5.2 | SC-34 |
| NIST 800-82 R3 | SC-34 |
| NIST 800-160 Vol2 R1 | SC-34 |
| Shared Assessments SIG 2025 | N.2 |
APAC (1)
| Framework | Mapping Values |
|---|---|
| APAC Malaysia RMiT 2025 | A10-B2(b)(ii) |
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
Secure Engineering & Architecture (SEA) domain capabilities are ad hoc and inconsistent. Capability criteria associated with this control may include: ▪ Policies, standards & procedures associated with SEA domain capabilities provide limited coverage due to the depth and breadth of the existing documentation. ▪ Security engineering-related activities are decentralized (e.g., a localized/regionalized function) and uses non-standardized methods to implement secure, resilient and compliant practices. ▪ IT and/or cybersecurity personnel use an informal process to design, build and maintain secure, compliant and resilient solutions.
Level 2 — Planned & Tracked
Secure Engineering & Architecture (SEA) 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 SEA domain capabilities are formally documented and centrally-managed by the entity. ▪ Standardized Operating Procedures (SOP) associated with SEA 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 SEA domain capabilities to address applicable statutory, regulatory and/or contractual requirements for Technology Assets, Applications, Services and/or Data (TAASD). ▪ Secure engineering and architecture-related controls are primarily administrative and preventative in nature (e.g., policies, standards and procedures & guidelines). ▪ Secure engineering and architecture 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 and/or cybersecurity personnel define entity-specific secure engineering practices to protect the Confidentiality, Integrity, Availability and Safety (CIAS) of the entity's TAASD. ▪ IT and/or cybersecurity personnel align secure engineering practices with the entity's broader IT architecture practices. ▪ IT and/or cybersecurity personnel use secure engineering practices to influence Secure Baseline Configurations (SBC).
Level 3 — Well Defined
Secure Engineering & Architecture (SEA) 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 SEA 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 SEA domain capabilities are well-documented and kept current by process owners. ▪ A cybersecurity engineering / architecture team, or similar function, is appropriately staffed and supported to implement and maintain RSK domain capabilities. ▪ Technology is leveraged to enhance the efficiency and accuracy of secure engineering management operations (e.g., project 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 SEA 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 secure engineering principles on all applicable Technology Assets, Applications and/or Services (TAAS). ▪ An implemented and operational capability exists to utilize non-modifiable executable programs that load and execute the operating environment and applications from hardware-enforced, read-only media.
Level 4 — Quantitatively Controlled
Secure Engineering & Architecture (SEA) 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
- SEA-26_A01 system components for which the operating environment and applications are to be loaded and executed from hardware-enforced, read-only media are defined.
- SEA-26_A02 applications to be loaded and executed from hardware-enforced, read-only media are defined.
- SEA-26_A03 the operating environment for system components is loaded and executed from hardware-enforced, read-only media.
- SEA-26_A04 applications for system components are loaded and executed from hardware-enforced, read-only media.
Technology Recommendations
Micro/Small
- Note: Typically not required at this size
Small
- Secure Boot enabled on endpoints
Medium
- UEFI Secure Boot and firmware protections enabled by baseline
- Read-only/immutable OS images where supported
Large
- Secure Boot, measured boot and firmware integrity (e.g., Windows Defender System Guard, TPM attestation)
- Immutable infrastructure images
Enterprise
- Enterprise hardware-rooted trust (Secure Boot, measured boot, remote attestation)
- Immutable OS/appliance images for critical systems
- Firmware integrity monitoring