ac-3-4-discretionary-access-control

name	AC-3(4)_discretionary-access-control
description	Enforce [organization-defined] over the set of covered subjects and objects specified in the policy, and where the policy specifies that a subject tha
category	authorization
version	5.2.0
author	cyberstrike-official
tags	["nist","sp800-53","rev5","ac-3-4","ac","enhancement"]
tech_stack	["aws","azure","gcp","linux","windows"]
cwe_ids	["CWE-284"]
chains_with	[]
prerequisites	["AC-3"]
severity_boost	{}

AC-3(4) Discretionary Access Control

Enhancement of: AC-3

High-Level Description

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

When discretionary access control policies are implemented, subjects are not constrained with regard to what actions they can take with information for which they have already been granted access. Thus, subjects that have been granted access to information are not prevented from passing the information to other subjects or objects (i.e., subjects have the discretion to pass). Discretionary access control can operate in conjunction with mandatory access control as described in AC-3(3) and AC-3(15) . A subject that is constrained in its operation by mandatory access control policies can still operate under the less rigorous constraints of discretionary access control. Therefore, while AC-3(3) imposes constraints that prevent a subject from passing information to another subject operating at a different impact or classification level, AC-3(4) permits the subject to pass the information to any subject at the same impact or classification level. The policy is bounded by the system. Once the information is passed outside of system control, additional means may be required to ensure that the constraints remain in effect. While traditional definitions of discretionary access control require identity-based access control, that limitation is not required for this particular use of discretionary access control.

What to Check

• Verify AC-3(4) Discretionary Access Control is documented in SSP
• Validate all 5 control requirements are implemented
• Confirm control is operating effectively
• Review evidence of continuous monitoring for AC-3(4)
• Verify enhancement builds upon base control AC-3

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for AC-3(4) 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