# AC-4(6)_metadata

> Enforce information flow control based on [organization-defined].

- Skill: `cyberstrikeus/ac-4-6-metadata` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/ac-4-6-metadata`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/ac-4-6-metadata/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/ac-4-6-metadata

---


# AC-4(6) Metadata

> **Enhancement of:** AC-4

## High-Level Description

**Family:** Access Control (AC)
**Framework:** NIST SP 800-53 Rev 5

Metadata is information that describes the characteristics of data. Metadata can include structural metadata describing data structures or descriptive metadata describing data content. Enforcement of allowed information flows based on metadata enables simpler and more effective flow control. Organizations consider the trustworthiness of metadata regarding data accuracy (i.e., knowledge that the metadata values are correct with respect to the data), data integrity (i.e., protecting against unauthorized changes to metadata tags), and the binding of metadata to the data payload (i.e., employing sufficiently strong binding techniques with appropriate assurance).

## What to Check

- [ ] Verify AC-4(6) Metadata is documented in SSP
- [ ] Confirm control is operating effectively
- [ ] Review evidence of continuous monitoring for AC-4(6)
- [ ] Verify enhancement builds upon base control AC-4

## How to Test

### Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for AC-4(6) 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

Enforce information flow control based on [organization-defined].

### Implementation Guidance

Metadata is information that describes the characteristics of data. Metadata can include structural metadata describing data structures or descriptive metadata describing data content. Enforcement of allowed information flows based on metadata enables simpler and more effective flow control. Organizations consider the trustworthiness of metadata regarding data accuracy (i.e., knowledge that the metadata values are correct with respect to the data), data integrity (i.e., protecting against unauthorized changes to metadata tags), and the binding of metadata to the data payload (i.e., employing sufficiently strong binding techniques with appropriate assurance).

## Risk Assessment

| Finding                          | Severity | Impact                    |
| -------------------------------- | -------- | ------------------------- |
| AC-4(6) Metadata not implemented | High     | Access Control            |
| AC-4(6) partially implemented    | Medium   | Incomplete Access Control |

## CWE Categories

| CWE ID  | Title                   |
| ------- | ----------------------- |
| CWE-284 | Improper Access Control |

## References

- [NIST SP 800-53 Rev 5 - AC-4(6)](https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_1/home?element=ac-4.6)
- [NIST SP 800-53A Rev 5 (Assessment Procedures)](https://csrc.nist.gov/pubs/sp/800/53/a/r5/final)
- [NIST SP 800-53 Rev 5 Full Catalog](https://csrc.nist.gov/pubs/sp/800/53/r5/upd1/final)

## Checklist

- [ ] Control documented in SSP
- [ ] Implementation evidence collected
- [ ] Operating effectiveness validated
- [ ] Continuous monitoring in place
- [ ] Related controls (AC-16, SI-7) reviewed