SC 23(5) Allowed Certificate Authorities

---
name: "SC-23(5)_allowed-certificate-authorities"
description: "Only allow the use of [organization-defined] for verification of the establishment of protected sessions."
category: "configuration"
version: "5.2.0"
author: "cyberstrike-official"
tags:
  - nist
  - sp800-53
  - rev5
  - sc-23-5
  - sc
  - enhancement
tech_stack:
  - aws
  - azure
  - gcp
  - linux
  - windows
  - network
cwe_ids:
  - CWE-311
chains_with:
  - SC-12
  - SC-13
prerequisites:
  - SC-23
severity_boost:
  SC-12: "Chain with SC-12 for comprehensive security coverage"
  SC-13: "Chain with SC-13 for comprehensive security coverage"
---

# SC-23(5) Allowed Certificate Authorities

> **Enhancement of:** SC-23

## High-Level Description

**Family:** System and Communications Protection (SC)
**Framework:** NIST SP 800-53 Rev 5

Reliance on certificate authorities for the establishment of secure sessions includes the use of Transport Layer Security (TLS) certificates. These certificates, after verification by their respective certificate authorities, facilitate the establishment of protected sessions between web clients and web servers.

## What to Check

- [ ] Verify SC-23(5) Allowed Certificate Authorities is documented in SSP
- [ ] Confirm control is operating effectively
- [ ] Review evidence of continuous monitoring for SC-23(5)
- [ ] Verify enhancement builds upon base control SC-23

## How to Test

### Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SC-23(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 encryption and network controls | `cloud_audit_encryption`             |
| nmap            | Network scanning                      | `nmap -sV --script ssl-enum-ciphers` |

## Remediation Guide

### Control Statement

Only allow the use of [organization-defined] for verification of the establishment of protected sessions.

### Implementation Guidance

Reliance on certificate authorities for the establishment of secure sessions includes the use of Transport Layer Security (TLS) certificates. These certificates, after verification by their respective certificate authorities, facilitate the establishment of protected sessions between web clients and web servers.

## Risk Assessment

| Finding                                                  | Severity | Impact                                          |
| -------------------------------------------------------- | -------- | ----------------------------------------------- |
| SC-23(5) Allowed Certificate Authorities not implemented | High     | System and Communications Protection            |
| SC-23(5) partially implemented                           | Medium   | Incomplete System and Communications Protection |

## CWE Categories

| CWE ID  | Title                                |
| ------- | ------------------------------------ |
| CWE-311 | Missing Encryption of Sensitive Data |

## References

- [NIST SP 800-53 Rev 5 - SC-23(5)](https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_1/home?element=sc-23.5)
- [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 (SC-12, SC-13) reviewed