Ac 16 9 Attribute Reassignment

---
name: "AC-16(9)_attribute-reassignment-regrading-mechanisms"
description: "Change security and privacy attributes associated with information only via regrading mechanisms validated using [organization-defined]."
category: "authorization"
version: "5.2.0"
author: "cyberstrike-official"
tags:
  - nist
  - sp800-53
  - rev5
  - ac-16-9
  - ac
  - enhancement
tech_stack:
  - aws
  - azure
  - gcp
  - linux
  - windows
cwe_ids:
  - CWE-284
chains_with: []
prerequisites:
  - AC-16
severity_boost: {}
---

# AC-16(9) Attribute Reassignment — Regrading Mechanisms

> **Enhancement of:** AC-16

## High-Level Description

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

A regrading mechanism is a trusted process authorized to re-classify and re-label data in accordance with a defined policy exception. Validated regrading mechanisms are used by organizations to provide the requisite levels of assurance for attribute reassignment activities. The validation is facilitated by ensuring that regrading mechanisms are single purpose and of limited function. Since security and privacy attribute changes can directly affect policy enforcement actions, implementing trustworthy regrading mechanisms is necessary to help ensure that such mechanisms perform in a consistent and correct mode of operation.

## What to Check

- [ ] Verify AC-16(9) Attribute Reassignment — Regrading Mechanisms is documented in SSP
- [ ] Confirm control is operating effectively
- [ ] Review evidence of continuous monitoring for AC-16(9)
- [ ] Verify enhancement builds upon base control AC-16

## How to Test

### Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for AC-16(9) 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

Change security and privacy attributes associated with information only via regrading mechanisms validated using [organization-defined].

### Implementation Guidance

A regrading mechanism is a trusted process authorized to re-classify and re-label data in accordance with a defined policy exception. Validated regrading mechanisms are used by organizations to provide the requisite levels of assurance for attribute reassignment activities. The validation is facilitated by ensuring that regrading mechanisms are single purpose and of limited function. Since security and privacy attribute changes can directly affect policy enforcement actions, implementing trustworthy regrading mechanisms is necessary to help ensure that such mechanisms perform in a consistent and correct mode of operation.

## Risk Assessment

| Finding                                                                | Severity | Impact                    |
| ---------------------------------------------------------------------- | -------- | ------------------------- |
| AC-16(9) Attribute Reassignment — Regrading Mechanisms not implemented | High     | Access Control            |
| AC-16(9) partially implemented                                         | Medium   | Incomplete Access Control |

## CWE Categories

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

## References

- [NIST SP 800-53 Rev 5 - AC-16(9)](https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_1/home?element=ac-16.9)
- [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 (none) reviewed