cyberstrikeus AC-20(5) Portable Storage Devices — Prohibited Use
Enhancement of: AC-20
High-Level Description
Family: Access Control (AC) Framework: NIST SP 800-53 Rev 5
Limits on the use of organization-controlled portable storage devices in external systems include a complete prohibition of the use of such devices. Prohibiting such use is enforced using technical methods and/or nontechnical (i.e., process-based) methods.
What to Check
- Verify AC-20(5) Portable Storage Devices — Prohibited Use is documented in SSP
- Confirm control is operating effectively
- Review evidence of continuous monitoring for AC-20(5)
- Verify enhancement builds upon base control AC-20
How to Test
Step 1: Review Documentation
Examine the System Security Plan (SSP) and related artifacts for AC-20(5) 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 IAM policies and access controls | cloud_audit_iam_policies |
| hackbrowser | Test web application access controls | hackbrowser |
Remediation Guide
Control Statement
Prohibit the use of organization-controlled portable storage devices by authorized individuals on external systems.
Implementation Guidance
Limits on the use of organization-controlled portable storage devices in external systems include a complete prohibition of the use of such devices. Prohibiting such use is enforced using technical methods and/or nontechnical (i.e., process-based) methods.
Risk Assessment
| Finding | Severity | Impact |
|---|---|---|
| AC-20(5) Portable Storage Devices — Prohibited Use not implemented | High | Access Control |
| AC-20(5) partially implemented | Medium | Incomplete Access Control |
CWE Categories
| CWE ID | Title |
|---|---|
| CWE-284 | Improper Access Control |
References
- NIST SP 800-53 Rev 5 - AC-20(5)
- NIST SP 800-53A Rev 5 (Assessment Procedures)
- NIST SP 800-53 Rev 5 Full Catalog
Checklist
- Control documented in SSP
- Implementation evidence collected
- Operating effectiveness validated
- Continuous monitoring in place
- Related controls (MP-7, PL-4, PS-6, SC-41) reviewed