AC 4(3) Dynamic Information Flow Control

---
name: "AC-4(3)_dynamic-information-flow-control"
description: "Enforce [organization-defined]."
category: "authorization"
version: "5.2.0"
author: "cyberstrike-official"
tags:
  - nist
  - sp800-53
  - rev5
  - ac-4-3
  - ac
  - enhancement
tech_stack:
  - aws
  - azure
  - gcp
  - linux
  - windows
cwe_ids:
  - CWE-284
chains_with:
  - SI-4
prerequisites:
  - AC-4
severity_boost:
  SI-4: "Chain with SI-4 for comprehensive security coverage"
---

# AC-4(3) Dynamic Information Flow Control

> **Enhancement of:** AC-4

## High-Level Description

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

Organizational policies regarding dynamic information flow control include allowing or disallowing information flows based on changing conditions or mission or operational considerations. Changing conditions include changes in risk tolerance due to changes in the immediacy of mission or business needs, changes in the threat environment, and detection of potentially harmful or adverse events.

## What to Check

- [ ] Verify AC-4(3) Dynamic Information Flow Control is documented in SSP
- [ ] Confirm control is operating effectively
- [ ] Review evidence of continuous monitoring for AC-4(3)
- [ ] 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(3) 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 [organization-defined].

### Implementation Guidance

Organizational policies regarding dynamic information flow control include allowing or disallowing information flows based on changing conditions or mission or operational considerations. Changing conditions include changes in risk tolerance due to changes in the immediacy of mission or business needs, changes in the threat environment, and detection of potentially harmful or adverse events.

## Risk Assessment

| Finding                                                  | Severity | Impact                    |
| -------------------------------------------------------- | -------- | ------------------------- |
| AC-4(3) Dynamic Information Flow Control not implemented | High     | Access Control            |
| AC-4(3) 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(3)](https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_1/home?element=ac-4.3)
- [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 (SI-4) reviewed