Process Isolation
✓ LOW ✓ MODERATE ✓ HIGHRequirements NIST SOURCE
Maintain a separate execution domain for each executing system process.
Discussion (NIST Supplemental Guidance)
Systems can maintain separate execution domains for each executing process by assigning each process a separate address space. Each system process has a distinct address space so that communication between processes is performed in a manner controlled through the security functions, and one process cannot modify the executing code of another process. Maintaining separate execution domains for executing processes can be achieved, for example, by implementing separate address spaces. Process isolation technologies, including sandboxing or virtualization, logically separate software and firmware from other software, firmware, and data. Process isolation helps limit the access of potentially untrusted software to other system resources. The capability to maintain separate execution domains is available in commercial operating systems that employ multi-state processor technologies.
Enhancements NIST SOURCE
SC-39(1) Hardware Separation LOW MODERATE HIGH
Implement hardware separation mechanisms to facilitate process isolation.
Discussion
Hardware-based separation of system processes is generally less susceptible to compromise than software-based separation, thus providing greater assurance that the separation will be enforced. Hardware separation mechanisms include hardware memory management.
SC-39(2) Separate Execution Domain Per Thread LOW MODERATE HIGH
Maintain a separate execution domain for each thread in [multi-threaded processing].
Discussion
None.
Implementation Guidance
Original engineering commentary written for this explorer — not NIST source text and not authoritative guidance.
No engineering interpretation has been authored for SC-39 yet. This section is architected to receive it — see the Requirements and Assessment sections above for the authoritative NIST source content in the meantime.
Assessment
Assessment Objectives
- a separate execution domain is maintained for each executing system process.
Examine
[SELECT FROM: System design documentation; system architecture; independent verification and validation documentation; testing and evaluation documentation; other relevant documents or records].
Interview
[SELECT FROM: System developers/integrators; system security architect].
Test
[SELECT FROM: Mechanisms supporting and/or implementing separate execution domains for each executing process].
Overlays
STIGs & CCIs
No STIG checks or CCI mappings are currently loaded for SC-39. This section is architected to display, per product: STIG ID, Finding ID, Severity, Title, Description, Check, Fix, CCI, and NIST control mapping — but nothing is populated here until a real DISA STIG/CCI dataset is ingested.
Learn more about STIG/CCI integration →Evidence
Categorized from the SP 800-53A "Examine"/"Test" artifact list above by keyword — not an authoritative NIST evidence list.
Configuration
- System design documentation
- system architecture
Testing
- Mechanisms supporting and/or implementing separate execution domains for each executing process
Other Records
- independent verification and validation documentation
- testing and evaluation documentation
- other relevant documents or records