# SC-4_information-in-shared-system-resources

> Prevent unauthorized and unintended information transfer via shared system resources.

- Skill: `cyberstrikeus/sc-4-information-in-shared-system-resources` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/sc-4-information-in-shared-system-resources`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/sc-4-information-in-shared-system-resources/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- 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-4-information-in-shared-system-resources

---


# SC-4 Information in Shared System Resources

## High-Level Description

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

Preventing unauthorized and unintended information transfer via shared system resources stops information produced by the actions of prior users or roles (or the actions of processes acting on behalf of prior users or roles) from being available to current users or roles (or current processes acting on behalf of current users or roles) that obtain access to shared system resources after those resources have been released back to the system. Information in shared system resources also applies to encrypted representations of information. In other contexts, control of information in shared system resources is referred to as object reuse and residual information protection. Information in shared system resources does not address information remanence, which refers to the residual representation of data that has been nominally deleted; covert channels (including storage and timing channels), where shared system resources are manipulated to violate information flow restrictions; or components within systems for which there are only single users or roles.

## What to Check

- [ ] Verify SC-4 Information in Shared System Resources is documented in SSP
- [ ] Confirm control is operating effectively
- [ ] Review evidence of continuous monitoring for SC-4

## How to Test

### Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SC-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 unauthorized and unintended information transfer via shared system resources.

### Implementation Guidance

Preventing unauthorized and unintended information transfer via shared system resources stops information produced by the actions of prior users or roles (or the actions of processes acting on behalf of prior users or roles) from being available to current users or roles (or current processes acting on behalf of current users or roles) that obtain access to shared system resources after those resources have been released back to the system. Information in shared system resources also applies to encrypted representations of information. In other contexts, control of information in shared system resources is referred to as object reuse and residual information protection. Information in shared system resources does not address information remanence, which refers to the residual representation of data that has been nominally deleted; covert channels (including storage and timing channels), where shared system resources are manipulated to violate information flow restrictions; or components within systems for which there are only single users or roles.

## Risk Assessment

| Finding                                                     | Severity | Impact                                          |
| ----------------------------------------------------------- | -------- | ----------------------------------------------- |
| SC-4 Information in Shared System Resources not implemented | High     | System and Communications Protection            |
| SC-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-4](https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_1/home?element=sc-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 (AC-3, AC-4, SA-8) reviewed