Overview of NIST 800-171 Control 3.13.17
NIST 800-171 control 3.13.17 focuses on ensuring that data in transit is not altered, tampered with, or replayed in a manner that undermines its integrity. This control complements confidentiality protections by emphasizing trustworthiness and accuracy of information as it moves between systems, endpoints, and services.
Protecting data integrity is essential for environments handling Controlled Unclassified Information (CUI) and is a key expectation for CMMC Level 2 compliance. Integrity mechanisms deter tampering and support verifiable evidence that transmitted data arrived unchanged and unmanipulated.
What the Control Requires
Control 3.13.17 requires organizations to implement mechanisms that verify the integrity of data while in motion. This typically includes cryptographic protections, integrity validation protocols, and monitoring practices that detect unauthorized modifications.
- Integrity protections: Use cryptographic hashes, message authentication codes, and digital signatures to detect changes to data.
- Transport validation: Ensure protocols such as TLS provide both confidentiality and integrity validation through authenticated encryption.
- Replay protection: Guard against replay attacks by incorporating nonces or sequence validation for session-based exchanges.
- Anomaly detection: Monitor for unexpected data size, structure changes, or origin discrepancies that may signal integrity violations.
Why Integrity Matters
Data in transit can be vulnerable to tampering, insertion of malicious content, or replay attacks if protections are absent or misconfigured. Without integrity checks, encryption alone may hide unauthorized changes to data without alerting defenders.
Ensuring data integrity protects against undetected manipulation, preserves trust in automated processes, and supports reliable decision-making based on transmitted information.
Implementation Practices
Organizations often implement integrity protections in layers, combining protocol-level checks with application-level validation and monitoring. These practices help provide multiple points of verification and support audit readiness.
- TLS with authenticated encryption: Enforce TLS 1.2 or higher with authenticated encryption ciphers such as AES-GCM or ChaCha20-Poly1305 where applicable.
- Digital signatures: Apply signatures to files or payloads so recipients can verify origin and content integrity.
- Hash validations: Use cryptographic hashing to compare expected and actual data values during and after transfer.
- Replay defenses: Employ session tokens, nonces, or sequence numbers to prevent replay attacks.
Audit-Ready Integrity Controls Table
The table below outlines practical control activities, expected operational cadence, audit evidence artifacts, and accountable roles to support 3.13.17 implementation for assessment readiness.
| Control Activity | Implementation Requirement | Review Cadence | Audit Evidence | Accountable Role |
|---|---|---|---|---|
| Protocol configuration | Enable TLS 1.2+ with authenticated encryption | Continuous enforcement; quarterly review | Configuration settings, cipher lists, protocol audits | Network/Security Engineer |
| Data hashing | Apply cryptographic hashes to critical transfers | Per-transfer validation; monthly audit | Hash records, validation outcomes, exception logs | Application Owner |
| Digital signatures | Sign and verify payloads where applicable | Continuous; review on updates | Signature records, key management artifacts | Security Operations |
| Replay protection | Use nonces or sequence checks for sessions | Continuous; after-change verification | Session logs, sequence validation records | System Administrator |
| Anomaly monitoring | Collect and review logs for unexpected integrity issues | Alerts continuous; weekly review | Log archives, alerts, incident tickets | Security Operations |
Common Gaps to Avoid
- Encryption without integrity checks: Relying solely on confidentiality protections without verifying content integrity.
- Outdated protocols: Using legacy transport protocols that lack modern authenticated encryption.
- Missing verification: Not validating hashes or signatures upon receipt.
- Insufficient monitoring: Failing to collect or review integrity-related logs and alerts.
- No replay defenses: Allowing replay of valid messages without sequence or token validation.
FAQ
What does NIST 800-171 control 3.13.17 require?
It requires organizations to protect data in motion against alteration by using integrity mechanisms such as cryptographic hashes and validation checks.
What techniques help ensure data integrity in transit?
Techniques include TLS with integrity protection, message authentication codes, digital signatures, and replay protections for API and file transfers.
What evidence supports 3.13.17 for a CMMC Level 2 assessment?
Evidence typically includes protocol configurations, integrity check logs, alert records, validation outcomes, and documented anomaly investigations.