# SC-18(4)_prevent-automatic-execution

> Prevent the automatic execution of mobile code in [organization-defined] and enforce [organization-defined] prior to executing the code.

- Skill: `cyberstrikeus/sc-18-4-prevent-automatic-execution` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/sc-18-4-prevent-automatic-execution`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/sc-18-4-prevent-automatic-execution/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector CAUTION)
- 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/sc-18-4-prevent-automatic-execution

---


# SC-18(4) Prevent Automatic Execution

> **Enhancement of:** SC-18

## High-Level Description

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

Actions enforced before executing mobile code include prompting users prior to opening email attachments or clicking on web links. Preventing the automatic execution of mobile code includes disabling auto-execute features on system components that employ portable storage devices, such as compact discs, digital versatile discs, and universal serial bus devices.

## What to Check

- [ ] Verify SC-18(4) Prevent Automatic Execution is documented in SSP
- [ ] Confirm control is operating effectively
- [ ] Review evidence of continuous monitoring for SC-18(4)
- [ ] Verify enhancement builds upon base control SC-18

## How to Test

### Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SC-18(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

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

Prevent the automatic execution of mobile code in [organization-defined] and enforce [organization-defined] prior to executing the code.

### Implementation Guidance

Actions enforced before executing mobile code include prompting users prior to opening email attachments or clicking on web links. Preventing the automatic execution of mobile code includes disabling auto-execute features on system components that employ portable storage devices, such as compact discs, digital versatile discs, and universal serial bus devices.

## Risk Assessment

| Finding                                              | Severity | Impact                                          |
| ---------------------------------------------------- | -------- | ----------------------------------------------- |
| SC-18(4) Prevent Automatic Execution not implemented | High     | System and Communications Protection            |
| SC-18(4) 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-18(4)](https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_1/home?element=sc-18.4)
- [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