SC-39_process-isolation

DevOps & Security

Maintain a separate execution domain for each executing system process.

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/NIST/SP800-53_rev5/SC_system-and-communications-protection/SC-39_process-isolation/SKILL.md

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SC-39 Process Isolation

High-Level Description

Family: System and Communications Protection (SC) Framework: NIST SP 800-53 Rev 5

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.

What to Check

Verify SC-39 Process Isolation is documented in SSP
Confirm control is operating effectively
Review evidence of continuous monitoring for SC-39

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SC-39 implementation details. Verify the organization has documented how this control is satisfied.

Step 2: Validate Implementation

# For cloud environments, use cloud-audit-mcp tools
# For on-premises, review system configurations directly

# Example: Check if account management policies exist
grep -r "account.management\|access.control" /etc/security/ 2>/dev/null

Step 3: Test Operating Effectiveness

Verify the control is actively functioning, not just documented. Check logs, configurations, and operational evidence.

Tools

Tool	Purpose	Usage
cloud-audit-mcp	Check encryption and network controls	`cloud_audit_encryption`
nmap	Network scanning	`nmap -sV --script ssl-enum-ciphers`

Remediation Guide

Control Statement

Maintain a separate execution domain for each executing system process.

Implementation Guidance

Risk Assessment

Finding	Severity	Impact
SC-39 Process Isolation not implemented	High	System and Communications Protection
SC-39 partially implemented	Medium	Incomplete System and Communications Protection

CWE Categories

CWE ID	Title
CWE-311	Missing Encryption of Sensitive Data

References

Checklist

Control documented in SSP
Implementation evidence collected
Operating effectiveness validated
Continuous monitoring in place
Related controls (AC-3, AC-4, AC-6, AC-25, SA-8) reviewed