Mapped to NIST 800-171 Requirement: 3.5.3
CMMC Assessment Objective: IA.L2-3.5.3[b]
What This Objective Means
Once you’ve identified which accounts need replay-resistant authentication (IA.L2-3.5.3[a]), this control checks whether those accounts are actually enforced to use it.
Replay-resistant authentication ensures that credentials—such as passwords, tokens, or session data—cannot be reused or intercepted by a malicious actor. The system should never allow the same credentials to be used more than once in a session or without revalidation.
This applies to:
• Remote user accounts
• API keys or service credentials
• Privileged users accessing CUI systems
• Web-based or cloud-based authentication flows
Why It Matters
If credentials can be replayed:
• Attackers can hijack sessions using sniffed or stolen credentials
• Authentication bypass may go undetected
• Session integrity and access logs may become unreliable
• Privileged systems could be compromised without triggering alerts
Enforcing replay resistance is essential for secure, modern authentication.
How to Implement It
1. Require Secure Protocols
• Enforce HTTPS, SSH, or other encrypted protocols that challenge each authentication attempt
• Disable basic authentication methods that transmit static credentials
2. Use Token-Based or Challenge-Response Authentication
• For APIs and services, require time-limited tokens or challenge-response exchanges
• For user sessions, ensure MFA or OTP-based solutions are in use
3. Configure Endpoint and Server Authentication Settings
• Windows: Enable NTLMv2 or Kerberos, disable legacy authentication
• Linux: Configure PAM modules for secure password and token use
4. Harden Session Management
• Set session expiration and re-authentication requirements
• Disable credential caching and auto-login options
5. Monitor for Violations
• Review logs for replay attempts, duplicate session tokens, or access anomalies
Evidence the Assessor Will Look For
• Authentication configuration files or settings enforcing replay resistance
• Logs showing secure protocols and authentication methods in use
• Screenshots or exports from MFA, token management, or session tools
• Documentation mapping accounts to replay-resistant authentication enforcement
Common Gaps
• Secure authentication tools are in place but not enforced for all accounts
• API credentials are static or reused indefinitely
• Remote login methods allow reuse of session cookies or tokens
• Older authentication protocols are enabled by default
How Cuick Trac Helps
Cuick Trac supports this requirement by:
• Requiring replay-resistant authentication methods for all remote and privileged users
• Enforcing secure protocols (HTTPS, RDP with NLA, SSH) across the enclave
• Automatically rejecting stale or reused credentials and session tokens
• Helping configure and validate replay-resistant authentication in endpoint and server settings
• Providing audit-ready documentation and configuration visibility
With Cuick Trac, secure authentication isn’t a feature—it’s a requirement.
Final CTA
Replay resistance is only effective if it’s enforced.
Schedule a Cuick Trac demo and make sure your authentication controls stand up to real-world attacks.