Mapped to NIST 800-171 Requirement: 3.5.3
CMMC Assessment Objective: IA.L2-3.5.3[a]
What This Objective Means
Before you can implement replay resistance, you must determine which accounts require it. This typically includes any accounts that:
• Access systems over a network (especially untrusted networks)
• Have elevated privileges
• Interact with CUI
• Are used for remote or API-based authentication
Replay-resistant mechanisms prevent attackers from capturing and reusing authentication data—such as passwords or tokens—to log in as a legitimate user.
Why It Matters
Without replay resistance:
• Stolen credentials (e.g., via network sniffing or phishing) can be reused
• Attackers can mimic legitimate sessions
• Single sign-on or API tokens may be exposed
• Systems are left vulnerable to session hijacking and man-in-the-middle attacks
Identifying vulnerable accounts is the first step toward preventing this.
How to Implement It
1. Identify All Account Types
• User accounts
• Administrative or privileged accounts
• Service accounts
• Remote access users
• API-based or system-to-system accounts
2. Classify Access Context
• Which accounts access systems over networks (especially externally)
• Which accounts access sensitive systems or data
3. Determine Replay Resistance Needs
• Flag account types that:
◦ Authenticate remotely
◦ Use shared credentials
◦ Are involved in programmatic access
4. Document Your Identification Process
• Maintain an inventory or matrix of account types and replay resistance requirements
• Reference this documentation in your SSP or Access Control Policy
Evidence the Assessor Will Look For
• List of account types requiring replay-resistant authentication
• Documentation showing how account classification was done
• Role-based or risk-based rationale for requiring replay resistance
• System diagrams or access flow diagrams identifying risk points
Common Gaps
• Replay resistance applied inconsistently or assumed rather than documented
• API/service accounts not included in the analysis
• No documentation showing how decisions were made
• Remote users not required to use secure methods
How Cuick Trac Helps
Cuick Trac supports this control by:
• Segmenting account types and enforcing secure authentication mechanisms based on role and access level
• Ensuring all remote and privileged accounts use replay-resistant methods by default
• Helping organizations document which account types are subject to enhanced controls
• Disabling insecure authentication protocols and enforcing encrypted sessions
With Cuick Trac, identifying which accounts need stronger authentication is streamlined, documented, and enforced.
Final CTA
Replay attacks exploit visibility gaps. The first step to closing them is knowing where you’re exposed.
Schedule a Cuick Trac demo to map out which accounts need replay resistance—and how we help enforce it.